Sweden-Number/dlls/winegstreamer/wg_parser.c

/*
 * GStreamer parser backend
 *
 * Copyright 2010 Maarten Lankhorst for CodeWeavers
 * Copyright 2010 Aric Stewart for CodeWeavers
 * Copyright 2019-2020 Zebediah Figura
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

#if 0
#pragma makedep unix
#endif

#include "config.h"
#include "ntstatus.h"
#define WIN32_NO_STATUS
#include "gst_private.h"
#include "winternl.h"

#include <gst/gst.h>
#include <gst/video/video.h>
#include <gst/audio/audio.h>

/* GStreamer callbacks may be called on threads not created by Wine, and
 * therefore cannot access the Wine TEB. This means that we must use GStreamer
 * debug logging instead of Wine debug logging. In order to be safe we forbid
 * any use of Wine debug logging in this entire file. */

GST_DEBUG_CATEGORY_STATIC(wine);
#define GST_CAT_DEFAULT wine

struct wg_parser
{
    BOOL (*init_gst)(struct wg_parser *parser);

    struct wg_parser_stream **streams;
    unsigned int stream_count;

    GstElement *container, *decodebin;
    GstBus *bus;
    GstPad *my_src, *their_sink;

    guint64 file_size, start_offset, next_offset, stop_offset;
    guint64 next_pull_offset;

    pthread_t push_thread;

    pthread_mutex_t mutex;

    pthread_cond_t init_cond;
    bool no_more_pads, has_duration, error;

    pthread_cond_t read_cond, read_done_cond;
    struct
    {
        void *data;
        uint64_t offset;
        uint32_t size;
        bool done;
        bool ret;
    } read_request;

    bool flushing, sink_connected;
};

struct wg_parser_stream
{
    struct wg_parser *parser;

    GstPad *their_src, *post_sink, *post_src, *my_sink;
    GstElement *flip;
    GstSegment segment;
    struct wg_format preferred_format, current_format;

    pthread_cond_t event_cond, event_empty_cond;
    struct wg_parser_event event;
    GstBuffer *buffer;
    GstMapInfo map_info;

    bool flushing, eos, enabled, has_caps;

    uint64_t duration;
};

static enum wg_audio_format wg_audio_format_from_gst(GstAudioFormat format)
{
    switch (format)
    {
        case GST_AUDIO_FORMAT_U8:
            return WG_AUDIO_FORMAT_U8;
        case GST_AUDIO_FORMAT_S16LE:
            return WG_AUDIO_FORMAT_S16LE;
        case GST_AUDIO_FORMAT_S24LE:
            return WG_AUDIO_FORMAT_S24LE;
        case GST_AUDIO_FORMAT_S32LE:
            return WG_AUDIO_FORMAT_S32LE;
        case GST_AUDIO_FORMAT_F32LE:
            return WG_AUDIO_FORMAT_F32LE;
        case GST_AUDIO_FORMAT_F64LE:
            return WG_AUDIO_FORMAT_F64LE;
        default:
            return WG_AUDIO_FORMAT_UNKNOWN;
    }
}

static uint32_t wg_channel_position_from_gst(GstAudioChannelPosition position)
{
    static const uint32_t position_map[] =
    {
        SPEAKER_FRONT_LEFT,
        SPEAKER_FRONT_RIGHT,
        SPEAKER_FRONT_CENTER,
        SPEAKER_LOW_FREQUENCY,
        SPEAKER_BACK_LEFT,
        SPEAKER_BACK_RIGHT,
        SPEAKER_FRONT_LEFT_OF_CENTER,
        SPEAKER_FRONT_RIGHT_OF_CENTER,
        SPEAKER_BACK_CENTER,
        0,
        SPEAKER_SIDE_LEFT,
        SPEAKER_SIDE_RIGHT,
        SPEAKER_TOP_FRONT_LEFT,
        SPEAKER_TOP_FRONT_RIGHT,
        SPEAKER_TOP_FRONT_CENTER,
        SPEAKER_TOP_CENTER,
        SPEAKER_TOP_BACK_LEFT,
        SPEAKER_TOP_BACK_RIGHT,
        0,
        0,
        SPEAKER_TOP_BACK_CENTER,
    };

    if (position < ARRAY_SIZE(position_map))
        return position_map[position];
    return 0;
}

static uint32_t wg_channel_mask_from_gst(const GstAudioInfo *info)
{
    uint32_t mask = 0, position;
    unsigned int i;

    for (i = 0; i < GST_AUDIO_INFO_CHANNELS(info); ++i)
    {
        if (!(position = wg_channel_position_from_gst(GST_AUDIO_INFO_POSITION(info, i))))
        {
            GST_WARNING("Unsupported channel %#x.", GST_AUDIO_INFO_POSITION(info, i));
            return 0;
        }
        /* Make sure it's also in WinMM order. WinMM mandates that channels be
         * ordered, as it were, from least to most significant SPEAKER_* bit.
         * Hence we fail if the current channel was already specified, or if any
         * higher bit was already specified. */
        if (mask & ~(position - 1))
        {
            GST_WARNING("Unsupported channel order.");
            return 0;
        }
        mask |= position;
    }
    return mask;
}

static void wg_format_from_audio_info(struct wg_format *format, const GstAudioInfo *info)
{
    format->major_type = WG_MAJOR_TYPE_AUDIO;
    format->u.audio.format = wg_audio_format_from_gst(GST_AUDIO_INFO_FORMAT(info));
    format->u.audio.channels = GST_AUDIO_INFO_CHANNELS(info);
    format->u.audio.channel_mask = wg_channel_mask_from_gst(info);
    format->u.audio.rate = GST_AUDIO_INFO_RATE(info);
}

static enum wg_video_format wg_video_format_from_gst(GstVideoFormat format)
{
    switch (format)
    {
        case GST_VIDEO_FORMAT_BGRA:
            return WG_VIDEO_FORMAT_BGRA;
        case GST_VIDEO_FORMAT_BGRx:
            return WG_VIDEO_FORMAT_BGRx;
        case GST_VIDEO_FORMAT_BGR:
            return WG_VIDEO_FORMAT_BGR;
        case GST_VIDEO_FORMAT_RGB15:
            return WG_VIDEO_FORMAT_RGB15;
        case GST_VIDEO_FORMAT_RGB16:
            return WG_VIDEO_FORMAT_RGB16;
        case GST_VIDEO_FORMAT_AYUV:
            return WG_VIDEO_FORMAT_AYUV;
        case GST_VIDEO_FORMAT_I420:
            return WG_VIDEO_FORMAT_I420;
        case GST_VIDEO_FORMAT_NV12:
            return WG_VIDEO_FORMAT_NV12;
        case GST_VIDEO_FORMAT_UYVY:
            return WG_VIDEO_FORMAT_UYVY;
        case GST_VIDEO_FORMAT_YUY2:
            return WG_VIDEO_FORMAT_YUY2;
        case GST_VIDEO_FORMAT_YV12:
            return WG_VIDEO_FORMAT_YV12;
        case GST_VIDEO_FORMAT_YVYU:
            return WG_VIDEO_FORMAT_YVYU;
        default:
            return WG_VIDEO_FORMAT_UNKNOWN;
    }
}

static void wg_format_from_video_info(struct wg_format *format, const GstVideoInfo *info)
{
    format->major_type = WG_MAJOR_TYPE_VIDEO;
    format->u.video.format = wg_video_format_from_gst(GST_VIDEO_INFO_FORMAT(info));
    format->u.video.width = GST_VIDEO_INFO_WIDTH(info);
    format->u.video.height = GST_VIDEO_INFO_HEIGHT(info);
    format->u.video.fps_n = GST_VIDEO_INFO_FPS_N(info);
    format->u.video.fps_d = GST_VIDEO_INFO_FPS_D(info);
}

static void wg_format_from_caps_audio_mpeg(struct wg_format *format, const GstCaps *caps)
{
    const GstStructure *structure = gst_caps_get_structure(caps, 0);
    gint layer, channels, rate;

    if (!gst_structure_get_int(structure, "layer", &layer))
    {
        GST_WARNING("Missing \"layer\" value.");
        return;
    }
    if (!gst_structure_get_int(structure, "channels", &channels))
    {
        GST_WARNING("Missing \"channels\" value.");
        return;
    }
    if (!gst_structure_get_int(structure, "rate", &rate))
    {
        GST_WARNING("Missing \"rate\" value.");
        return;
    }

    format->major_type = WG_MAJOR_TYPE_AUDIO;

    if (layer == 1)
        format->u.audio.format = WG_AUDIO_FORMAT_MPEG1_LAYER1;
    else if (layer == 2)
        format->u.audio.format = WG_AUDIO_FORMAT_MPEG1_LAYER2;
    else if (layer == 3)
        format->u.audio.format = WG_AUDIO_FORMAT_MPEG1_LAYER3;

    format->u.audio.channels = channels;
    format->u.audio.rate = rate;
}

static void wg_format_from_caps_video_cinepak(struct wg_format *format, const GstCaps *caps)
{
    const GstStructure *structure = gst_caps_get_structure(caps, 0);
    gint width, height, fps_n, fps_d;

    if (!gst_structure_get_int(structure, "width", &width))
    {
        GST_WARNING("Missing \"width\" value.");
        return;
    }
    if (!gst_structure_get_int(structure, "height", &height))
    {
        GST_WARNING("Missing \"height\" value.");
        return;
    }
    if (!gst_structure_get_fraction(structure, "framerate", &fps_n, &fps_d))
    {
        fps_n = 0;
        fps_d = 1;
    }

    format->major_type = WG_MAJOR_TYPE_VIDEO;
    format->u.video.format = WG_VIDEO_FORMAT_CINEPAK;
    format->u.video.width = width;
    format->u.video.height = height;
    format->u.video.fps_n = fps_n;
    format->u.video.fps_d = fps_d;
}

static void wg_format_from_caps(struct wg_format *format, const GstCaps *caps)
{
    const GstStructure *structure = gst_caps_get_structure(caps, 0);
    const char *name = gst_structure_get_name(structure);

    memset(format, 0, sizeof(*format));

    if (!strcmp(name, "audio/x-raw"))
    {
        GstAudioInfo info;

        if (gst_audio_info_from_caps(&info, caps))
            wg_format_from_audio_info(format, &info);
    }
    else if (!strcmp(name, "video/x-raw"))
    {
        GstVideoInfo info;

        if (gst_video_info_from_caps(&info, caps))
            wg_format_from_video_info(format, &info);
    }
    else if (!strcmp(name, "audio/mpeg"))
    {
        wg_format_from_caps_audio_mpeg(format, caps);
    }
    else if (!strcmp(name, "video/x-cinepak"))
    {
        wg_format_from_caps_video_cinepak(format, caps);
    }
    else
    {
        gchar *str = gst_caps_to_string(caps);

        GST_FIXME("Unhandled caps %s.", str);
        g_free(str);
    }
}

static GstAudioFormat wg_audio_format_to_gst(enum wg_audio_format format)
{
    switch (format)
    {
        case WG_AUDIO_FORMAT_U8:    return GST_AUDIO_FORMAT_U8;
        case WG_AUDIO_FORMAT_S16LE: return GST_AUDIO_FORMAT_S16LE;
        case WG_AUDIO_FORMAT_S24LE: return GST_AUDIO_FORMAT_S24LE;
        case WG_AUDIO_FORMAT_S32LE: return GST_AUDIO_FORMAT_S32LE;
        case WG_AUDIO_FORMAT_F32LE: return GST_AUDIO_FORMAT_F32LE;
        case WG_AUDIO_FORMAT_F64LE: return GST_AUDIO_FORMAT_F64LE;
        default: return GST_AUDIO_FORMAT_UNKNOWN;
    }
}

static void wg_channel_mask_to_gst(GstAudioChannelPosition *positions, uint32_t mask, uint32_t channel_count)
{
    const uint32_t orig_mask = mask;
    unsigned int i;
    DWORD bit;

    static const GstAudioChannelPosition position_map[] =
    {
        GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT,
        GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT,
        GST_AUDIO_CHANNEL_POSITION_FRONT_CENTER,
        GST_AUDIO_CHANNEL_POSITION_LFE1,
        GST_AUDIO_CHANNEL_POSITION_REAR_LEFT,
        GST_AUDIO_CHANNEL_POSITION_REAR_RIGHT,
        GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER,
        GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER,
        GST_AUDIO_CHANNEL_POSITION_REAR_CENTER,
        GST_AUDIO_CHANNEL_POSITION_SIDE_LEFT,
        GST_AUDIO_CHANNEL_POSITION_SIDE_RIGHT,
        GST_AUDIO_CHANNEL_POSITION_TOP_CENTER,
        GST_AUDIO_CHANNEL_POSITION_TOP_FRONT_LEFT,
        GST_AUDIO_CHANNEL_POSITION_TOP_FRONT_CENTER,
        GST_AUDIO_CHANNEL_POSITION_TOP_FRONT_RIGHT,
        GST_AUDIO_CHANNEL_POSITION_TOP_REAR_LEFT,
        GST_AUDIO_CHANNEL_POSITION_TOP_REAR_CENTER,
        GST_AUDIO_CHANNEL_POSITION_TOP_REAR_RIGHT,
    };

    for (i = 0; i < channel_count; ++i)
    {
        positions[i] = GST_AUDIO_CHANNEL_POSITION_NONE;
        if (BitScanForward(&bit, mask))
        {
            if (bit < ARRAY_SIZE(position_map))
                positions[i] = position_map[bit];
            else
                GST_WARNING("Invalid channel mask %#x.\n", orig_mask);
            mask &= ~(1 << bit);
        }
        else
        {
            GST_WARNING("Incomplete channel mask %#x.\n", orig_mask);
        }
    }
}

static GstCaps *wg_format_to_caps_audio(const struct wg_format *format)
{
    GstAudioChannelPosition positions[32];
    GstAudioFormat audio_format;
    GstAudioInfo info;

    if ((audio_format = wg_audio_format_to_gst(format->u.audio.format)) == GST_AUDIO_FORMAT_UNKNOWN)
        return NULL;

    wg_channel_mask_to_gst(positions, format->u.audio.channel_mask, format->u.audio.channels);
    gst_audio_info_set_format(&info, audio_format, format->u.audio.rate, format->u.audio.channels, positions);
    return gst_audio_info_to_caps(&info);
}

static GstVideoFormat wg_video_format_to_gst(enum wg_video_format format)
{
    switch (format)
    {
        case WG_VIDEO_FORMAT_BGRA:  return GST_VIDEO_FORMAT_BGRA;
        case WG_VIDEO_FORMAT_BGRx:  return GST_VIDEO_FORMAT_BGRx;
        case WG_VIDEO_FORMAT_BGR:   return GST_VIDEO_FORMAT_BGR;
        case WG_VIDEO_FORMAT_RGB15: return GST_VIDEO_FORMAT_RGB15;
        case WG_VIDEO_FORMAT_RGB16: return GST_VIDEO_FORMAT_RGB16;
        case WG_VIDEO_FORMAT_AYUV:  return GST_VIDEO_FORMAT_AYUV;
        case WG_VIDEO_FORMAT_I420:  return GST_VIDEO_FORMAT_I420;
        case WG_VIDEO_FORMAT_NV12:  return GST_VIDEO_FORMAT_NV12;
        case WG_VIDEO_FORMAT_UYVY:  return GST_VIDEO_FORMAT_UYVY;
        case WG_VIDEO_FORMAT_YUY2:  return GST_VIDEO_FORMAT_YUY2;
        case WG_VIDEO_FORMAT_YV12:  return GST_VIDEO_FORMAT_YV12;
        case WG_VIDEO_FORMAT_YVYU:  return GST_VIDEO_FORMAT_YVYU;
        default: return GST_VIDEO_FORMAT_UNKNOWN;
    }
}

static GstCaps *wg_format_to_caps_video(const struct wg_format *format)
{
    GstVideoFormat video_format;
    GstVideoInfo info;
    unsigned int i;
    GstCaps *caps;

    if ((video_format = wg_video_format_to_gst(format->u.video.format)) == GST_VIDEO_FORMAT_UNKNOWN)
        return NULL;

    gst_video_info_set_format(&info, video_format, format->u.video.width, format->u.video.height);
    if ((caps = gst_video_info_to_caps(&info)))
    {
        /* Clear some fields that shouldn't prevent us from connecting. */
        for (i = 0; i < gst_caps_get_size(caps); ++i)
        {
            gst_structure_remove_fields(gst_caps_get_structure(caps, i),
                    "framerate", "pixel-aspect-ratio", "colorimetry", "chroma-site", NULL);
        }
    }
    return caps;
}

static GstCaps *wg_format_to_caps(const struct wg_format *format)
{
    switch (format->major_type)
    {
        case WG_MAJOR_TYPE_UNKNOWN:
            return NULL;
        case WG_MAJOR_TYPE_AUDIO:
            return wg_format_to_caps_audio(format);
        case WG_MAJOR_TYPE_VIDEO:
            return wg_format_to_caps_video(format);
    }
    assert(0);
    return NULL;
}

static bool wg_format_compare(const struct wg_format *a, const struct wg_format *b)
{
    if (a->major_type != b->major_type)
        return false;

    switch (a->major_type)
    {
        case WG_MAJOR_TYPE_UNKNOWN:
            return false;

        case WG_MAJOR_TYPE_AUDIO:
            return a->u.audio.format == b->u.audio.format
                    && a->u.audio.channels == b->u.audio.channels
                    && a->u.audio.rate == b->u.audio.rate;

        case WG_MAJOR_TYPE_VIDEO:
            /* Do not compare FPS. */
            return a->u.video.format == b->u.video.format
                    && a->u.video.width == b->u.video.width
                    && a->u.video.height == b->u.video.height;
    }

    assert(0);
    return false;
}

static uint32_t CDECL wg_parser_get_stream_count(struct wg_parser *parser)
{
    return parser->stream_count;
}

static struct wg_parser_stream * CDECL wg_parser_get_stream(struct wg_parser *parser, uint32_t index)
{
    return parser->streams[index];
}

static void CDECL wg_parser_begin_flush(struct wg_parser *parser)
{
    unsigned int i;

    pthread_mutex_lock(&parser->mutex);
    parser->flushing = true;
    pthread_mutex_unlock(&parser->mutex);

    for (i = 0; i < parser->stream_count; ++i)
    {
        if (parser->streams[i]->enabled)
            pthread_cond_signal(&parser->streams[i]->event_cond);
    }
}

static void CDECL wg_parser_end_flush(struct wg_parser *parser)
{
    pthread_mutex_lock(&parser->mutex);
    parser->flushing = false;
    pthread_mutex_unlock(&parser->mutex);
}

static bool CDECL wg_parser_get_read_request(struct wg_parser *parser,
        void **data, uint64_t *offset, uint32_t *size)
{
    pthread_mutex_lock(&parser->mutex);

    while (parser->sink_connected && !parser->read_request.data)
        pthread_cond_wait(&parser->read_cond, &parser->mutex);

    if (!parser->sink_connected)
    {
        pthread_mutex_unlock(&parser->mutex);
        return false;
    }

    *data = parser->read_request.data;
    *offset = parser->read_request.offset;
    *size = parser->read_request.size;

    pthread_mutex_unlock(&parser->mutex);
    return true;
}

static void CDECL wg_parser_complete_read_request(struct wg_parser *parser, bool ret)
{
    pthread_mutex_lock(&parser->mutex);
    parser->read_request.done = true;
    parser->read_request.ret = ret;
    parser->read_request.data = NULL;
    pthread_mutex_unlock(&parser->mutex);
    pthread_cond_signal(&parser->read_done_cond);
}

static void CDECL wg_parser_set_unlimited_buffering(struct wg_parser *parser)
{
    g_object_set(parser->decodebin, "max-size-buffers", G_MAXUINT, NULL);
    g_object_set(parser->decodebin, "max-size-time", G_MAXUINT64, NULL);
    g_object_set(parser->decodebin, "max-size-bytes", G_MAXUINT, NULL);
}

static void CDECL wg_parser_stream_get_preferred_format(struct wg_parser_stream *stream, struct wg_format *format)
{
    *format = stream->preferred_format;
}

static void CDECL wg_parser_stream_enable(struct wg_parser_stream *stream, const struct wg_format *format)
{
    stream->current_format = *format;
    stream->enabled = true;

    if (format->major_type == WG_MAJOR_TYPE_VIDEO)
    {
        switch (format->u.video.format)
        {
            case WG_VIDEO_FORMAT_BGRA:
            case WG_VIDEO_FORMAT_BGRx:
            case WG_VIDEO_FORMAT_BGR:
            case WG_VIDEO_FORMAT_RGB15:
            case WG_VIDEO_FORMAT_RGB16:
                gst_util_set_object_arg(G_OBJECT(stream->flip), "method", "vertical-flip");
                break;

            case WG_VIDEO_FORMAT_AYUV:
            case WG_VIDEO_FORMAT_I420:
            case WG_VIDEO_FORMAT_NV12:
            case WG_VIDEO_FORMAT_UYVY:
            case WG_VIDEO_FORMAT_YUY2:
            case WG_VIDEO_FORMAT_YV12:
            case WG_VIDEO_FORMAT_YVYU:
            case WG_VIDEO_FORMAT_UNKNOWN:
            case WG_VIDEO_FORMAT_CINEPAK:
                gst_util_set_object_arg(G_OBJECT(stream->flip), "method", "none");
                break;
        }
    }

    gst_pad_push_event(stream->my_sink, gst_event_new_reconfigure());
}

static void CDECL wg_parser_stream_disable(struct wg_parser_stream *stream)
{
    stream->enabled = false;
}

static bool CDECL wg_parser_stream_get_event(struct wg_parser_stream *stream, struct wg_parser_event *event)
{
    struct wg_parser *parser = stream->parser;

    pthread_mutex_lock(&parser->mutex);

    while (!parser->flushing && stream->event.type == WG_PARSER_EVENT_NONE)
        pthread_cond_wait(&stream->event_cond, &parser->mutex);

    if (parser->flushing)
    {
        pthread_mutex_unlock(&parser->mutex);
        GST_DEBUG("Filter is flushing.\n");
        return false;
    }

    *event = stream->event;

    if (stream->event.type != WG_PARSER_EVENT_BUFFER)
    {
        stream->event.type = WG_PARSER_EVENT_NONE;
        pthread_cond_signal(&stream->event_empty_cond);
    }
    pthread_mutex_unlock(&parser->mutex);

    return true;
}

static bool CDECL wg_parser_stream_copy_buffer(struct wg_parser_stream *stream,
        void *data, uint32_t offset, uint32_t size)
{
    struct wg_parser *parser = stream->parser;

    pthread_mutex_lock(&parser->mutex);

    if (!stream->buffer)
    {
        pthread_mutex_unlock(&parser->mutex);
        return false;
    }

    assert(stream->event.type == WG_PARSER_EVENT_BUFFER);
    assert(offset < stream->map_info.size);
    assert(offset + size <= stream->map_info.size);
    memcpy(data, stream->map_info.data + offset, size);

    pthread_mutex_unlock(&parser->mutex);
    return true;
}

static void CDECL wg_parser_stream_release_buffer(struct wg_parser_stream *stream)
{
    struct wg_parser *parser = stream->parser;

    pthread_mutex_lock(&parser->mutex);

    assert(stream->event.type == WG_PARSER_EVENT_BUFFER);

    gst_buffer_unmap(stream->buffer, &stream->map_info);
    gst_buffer_unref(stream->buffer);
    stream->buffer = NULL;
    stream->event.type = WG_PARSER_EVENT_NONE;

    pthread_mutex_unlock(&parser->mutex);
    pthread_cond_signal(&stream->event_empty_cond);
}

static uint64_t CDECL wg_parser_stream_get_duration(struct wg_parser_stream *stream)
{
    return stream->duration;
}

static bool CDECL wg_parser_stream_seek(struct wg_parser_stream *stream, double rate,
        uint64_t start_pos, uint64_t stop_pos, DWORD start_flags, DWORD stop_flags)
{
    GstSeekType start_type = GST_SEEK_TYPE_SET, stop_type = GST_SEEK_TYPE_SET;
    GstSeekFlags flags = 0;

    if (start_flags & AM_SEEKING_SeekToKeyFrame)
        flags |= GST_SEEK_FLAG_KEY_UNIT;
    if (start_flags & AM_SEEKING_Segment)
        flags |= GST_SEEK_FLAG_SEGMENT;
    if (!(start_flags & AM_SEEKING_NoFlush))
        flags |= GST_SEEK_FLAG_FLUSH;

    if ((start_flags & AM_SEEKING_PositioningBitsMask) == AM_SEEKING_NoPositioning)
        start_type = GST_SEEK_TYPE_NONE;
    if ((stop_flags & AM_SEEKING_PositioningBitsMask) == AM_SEEKING_NoPositioning)
        stop_type = GST_SEEK_TYPE_NONE;

    return gst_pad_push_event(stream->my_sink, gst_event_new_seek(rate,
            GST_FORMAT_TIME, flags, start_type, start_pos * 100, stop_type, stop_pos * 100));
}

static void CDECL wg_parser_stream_notify_qos(struct wg_parser_stream *stream,
        bool underflow, double proportion, int64_t diff, uint64_t timestamp)
{
    GstClockTime stream_time;
    GstEvent *event;

    /* We return timestamps in stream time, i.e. relative to the start of the
     * file (or other medium), but gst_event_new_qos() expects the timestamp in
     * running time. */
    stream_time = gst_segment_to_running_time(&stream->segment, GST_FORMAT_TIME, timestamp * 100);
    if (stream_time == -1)
    {
        /* This can happen legitimately if the sample falls outside of the
         * segment bounds. GStreamer elements shouldn't present the sample in
         * that case, but DirectShow doesn't care. */
        GST_LOG("Ignoring QoS event.\n");
        return;
    }

    if (!(event = gst_event_new_qos(underflow ? GST_QOS_TYPE_UNDERFLOW : GST_QOS_TYPE_OVERFLOW,
            proportion, diff * 100, stream_time)))
        GST_ERROR("Failed to create QOS event.\n");
    gst_pad_push_event(stream->my_sink, event);
}

static GstAutoplugSelectResult autoplug_select_cb(GstElement *bin, GstPad *pad,
        GstCaps *caps, GstElementFactory *fact, gpointer user)
{
    const char *name = gst_element_factory_get_longname(fact);

    GST_INFO("Using \"%s\".", name);

    if (strstr(name, "Player protection"))
    {
        GST_WARNING("Blacklisted a/52 decoder because it only works in Totem.");
        return GST_AUTOPLUG_SELECT_SKIP;
    }
    if (!strcmp(name, "Fluendo Hardware Accelerated Video Decoder"))
    {
        GST_WARNING("Disabled video acceleration since it breaks in wine.");
        return GST_AUTOPLUG_SELECT_SKIP;
    }
    return GST_AUTOPLUG_SELECT_TRY;
}

static void no_more_pads_cb(GstElement *element, gpointer user)
{
    struct wg_parser *parser = user;

    GST_DEBUG("parser %p.", parser);

    pthread_mutex_lock(&parser->mutex);
    parser->no_more_pads = true;
    pthread_mutex_unlock(&parser->mutex);
    pthread_cond_signal(&parser->init_cond);
}

static GstFlowReturn queue_stream_event(struct wg_parser_stream *stream,
        const struct wg_parser_event *event, GstBuffer *buffer)
{
    struct wg_parser *parser = stream->parser;

    /* Unlike request_buffer_src() [q.v.], we need to watch for GStreamer
     * flushes here. The difference is that we can be blocked by the streaming
     * thread not running (or itself flushing on the DirectShow side).
     * request_buffer_src() can only be blocked by the upstream source, and that
     * is solved by flushing the upstream source. */

    pthread_mutex_lock(&parser->mutex);
    while (!stream->flushing && stream->event.type != WG_PARSER_EVENT_NONE)
        pthread_cond_wait(&stream->event_empty_cond, &parser->mutex);
    if (stream->flushing)
    {
        pthread_mutex_unlock(&parser->mutex);
        GST_DEBUG("Filter is flushing; discarding event.");
        return GST_FLOW_FLUSHING;
    }
    if (buffer)
    {
        assert(GST_IS_BUFFER(buffer));
        if (!gst_buffer_map(buffer, &stream->map_info, GST_MAP_READ))
        {
            pthread_mutex_unlock(&parser->mutex);
            GST_ERROR("Failed to map buffer.\n");
            return GST_FLOW_ERROR;
        }
    }
    stream->event = *event;
    stream->buffer = buffer;
    pthread_mutex_unlock(&parser->mutex);
    pthread_cond_signal(&stream->event_cond);
    GST_LOG("Event queued.");
    return GST_FLOW_OK;
}

static gboolean sink_event_cb(GstPad *pad, GstObject *parent, GstEvent *event)
{
    struct wg_parser_stream *stream = gst_pad_get_element_private(pad);
    struct wg_parser *parser = stream->parser;

    GST_LOG("stream %p, type \"%s\".", stream, GST_EVENT_TYPE_NAME(event));

    switch (event->type)
    {
        case GST_EVENT_SEGMENT:
            if (stream->enabled)
            {
                struct wg_parser_event stream_event;
                const GstSegment *segment;

                gst_event_parse_segment(event, &segment);

                if (segment->format != GST_FORMAT_TIME)
                {
                    GST_FIXME("Unhandled format \"%s\".", gst_format_get_name(segment->format));
                    break;
                }

                gst_segment_copy_into(segment, &stream->segment);

                stream_event.type = WG_PARSER_EVENT_SEGMENT;
                stream_event.u.segment.position = segment->position / 100;
                stream_event.u.segment.stop = segment->stop / 100;
                stream_event.u.segment.rate = segment->rate * segment->applied_rate;
                queue_stream_event(stream, &stream_event, NULL);
            }
            break;

        case GST_EVENT_EOS:
            if (stream->enabled)
            {
                struct wg_parser_event stream_event;

                stream_event.type = WG_PARSER_EVENT_EOS;
                queue_stream_event(stream, &stream_event, NULL);
            }
            else
            {
                pthread_mutex_lock(&parser->mutex);
                stream->eos = true;
                pthread_mutex_unlock(&parser->mutex);
                pthread_cond_signal(&parser->init_cond);
            }
            break;

        case GST_EVENT_FLUSH_START:
            if (stream->enabled)
            {
                pthread_mutex_lock(&parser->mutex);

                stream->flushing = true;
                pthread_cond_signal(&stream->event_empty_cond);

                if (stream->event.type == WG_PARSER_EVENT_BUFFER)
                {
                    gst_buffer_unmap(stream->buffer, &stream->map_info);
                    gst_buffer_unref(stream->buffer);
                    stream->buffer = NULL;
                }
                stream->event.type = WG_PARSER_EVENT_NONE;

                pthread_mutex_unlock(&parser->mutex);
            }
            break;

        case GST_EVENT_FLUSH_STOP:
        {
            gboolean reset_time;

            gst_event_parse_flush_stop(event, &reset_time);

            if (reset_time)
                gst_segment_init(&stream->segment, GST_FORMAT_UNDEFINED);

            if (stream->enabled)
            {
                pthread_mutex_lock(&parser->mutex);
                stream->flushing = false;
                pthread_mutex_unlock(&parser->mutex);
            }
            break;
        }

        case GST_EVENT_CAPS:
        {
            GstCaps *caps;

            gst_event_parse_caps(event, &caps);
            pthread_mutex_lock(&parser->mutex);
            wg_format_from_caps(&stream->preferred_format, caps);
            stream->has_caps = true;
            pthread_mutex_unlock(&parser->mutex);
            pthread_cond_signal(&parser->init_cond);
            break;
        }

        default:
            GST_WARNING("Ignoring \"%s\" event.", GST_EVENT_TYPE_NAME(event));
    }
    gst_event_unref(event);
    return TRUE;
}

static GstFlowReturn sink_chain_cb(GstPad *pad, GstObject *parent, GstBuffer *buffer)
{
    struct wg_parser_stream *stream = gst_pad_get_element_private(pad);
    struct wg_parser_event stream_event;
    GstFlowReturn ret;

    GST_LOG("stream %p, buffer %p.", stream, buffer);

    if (!stream->enabled)
    {
        gst_buffer_unref(buffer);
        return GST_FLOW_OK;
    }

    stream_event.type = WG_PARSER_EVENT_BUFFER;

    /* FIXME: Should we use gst_segment_to_stream_time_full()? Under what
     * circumstances is the stream time not equal to the buffer PTS? Note that
     * this will need modification to wg_parser_stream_notify_qos() as well. */

    if ((stream_event.u.buffer.has_pts = GST_BUFFER_PTS_IS_VALID(buffer)))
        stream_event.u.buffer.pts = GST_BUFFER_PTS(buffer) / 100;
    if ((stream_event.u.buffer.has_duration = GST_BUFFER_DURATION_IS_VALID(buffer)))
        stream_event.u.buffer.duration = GST_BUFFER_DURATION(buffer) / 100;
    stream_event.u.buffer.discontinuity = GST_BUFFER_FLAG_IS_SET(buffer, GST_BUFFER_FLAG_DISCONT);
    stream_event.u.buffer.preroll = GST_BUFFER_FLAG_IS_SET(buffer, GST_BUFFER_FLAG_LIVE);
    stream_event.u.buffer.delta = GST_BUFFER_FLAG_IS_SET(buffer, GST_BUFFER_FLAG_DELTA_UNIT);
    stream_event.u.buffer.size = gst_buffer_get_size(buffer);

    /* Transfer our reference to the buffer to the stream object. */
    if ((ret = queue_stream_event(stream, &stream_event, buffer)) != GST_FLOW_OK)
        gst_buffer_unref(buffer);
    return ret;
}

static gboolean sink_query_cb(GstPad *pad, GstObject *parent, GstQuery *query)
{
    struct wg_parser_stream *stream = gst_pad_get_element_private(pad);

    GST_LOG("stream %p, type \"%s\".", stream, gst_query_type_get_name(query->type));

    switch (query->type)
    {
        case GST_QUERY_CAPS:
        {
            GstCaps *caps, *filter, *temp;

            gst_query_parse_caps(query, &filter);

            if (stream->enabled)
                caps = wg_format_to_caps(&stream->current_format);
            else
                caps = gst_caps_new_any();
            if (!caps)
                return FALSE;

            if (filter)
            {
                temp = gst_caps_intersect(caps, filter);
                gst_caps_unref(caps);
                caps = temp;
            }

            gst_query_set_caps_result(query, caps);
            gst_caps_unref(caps);
            return TRUE;
        }

        case GST_QUERY_ACCEPT_CAPS:
        {
            struct wg_format format;
            gboolean ret = TRUE;
            GstCaps *caps;

            if (!stream->enabled)
            {
                gst_query_set_accept_caps_result(query, TRUE);
                return TRUE;
            }

            gst_query_parse_accept_caps(query, &caps);
            wg_format_from_caps(&format, caps);
            ret = wg_format_compare(&format, &stream->current_format);
            if (!ret && gst_debug_category_get_threshold(GST_CAT_DEFAULT) >= GST_LEVEL_WARNING)
            {
                gchar *str = gst_caps_to_string(caps);
                GST_WARNING("Rejecting caps \"%s\".", str);
                g_free(str);
            }
            gst_query_set_accept_caps_result(query, ret);
            return TRUE;
        }

        default:
            return gst_pad_query_default (pad, parent, query);
    }
}

static GstElement *create_element(const char *name, const char *plugin_set)
{
    GstElement *element;

    if (!(element = gst_element_factory_make(name, NULL)))
        fprintf(stderr, "winegstreamer: failed to create %s, are %u-bit GStreamer \"%s\" plugins installed?\n",
                name, 8 * (unsigned int)sizeof(void *), plugin_set);
    return element;
}

static struct wg_parser_stream *create_stream(struct wg_parser *parser)
{
    struct wg_parser_stream *stream, **new_array;
    char pad_name[19];

    if (!(new_array = realloc(parser->streams, (parser->stream_count + 1) * sizeof(*parser->streams))))
        return NULL;
    parser->streams = new_array;

    if (!(stream = calloc(1, sizeof(*stream))))
        return NULL;

    gst_segment_init(&stream->segment, GST_FORMAT_UNDEFINED);

    stream->parser = parser;
    pthread_cond_init(&stream->event_cond, NULL);
    pthread_cond_init(&stream->event_empty_cond, NULL);

    sprintf(pad_name, "qz_sink_%u", parser->stream_count);
    stream->my_sink = gst_pad_new(pad_name, GST_PAD_SINK);
    gst_pad_set_element_private(stream->my_sink, stream);
    gst_pad_set_chain_function(stream->my_sink, sink_chain_cb);
    gst_pad_set_event_function(stream->my_sink, sink_event_cb);
    gst_pad_set_query_function(stream->my_sink, sink_query_cb);

    parser->streams[parser->stream_count++] = stream;
    return stream;
}

static void pad_added_cb(GstElement *element, GstPad *pad, gpointer user)
{
    struct wg_parser *parser = user;
    struct wg_parser_stream *stream;
    const char *name;
    GstCaps *caps;
    int ret;

    GST_LOG("parser %p, element %p, pad %p.", parser, element, pad);

    if (gst_pad_is_linked(pad))
        return;

    caps = gst_pad_query_caps(pad, NULL);
    name = gst_structure_get_name(gst_caps_get_structure(caps, 0));

    if (!(stream = create_stream(parser)))
        goto out;

    if (!strcmp(name, "video/x-raw"))
    {
        GstElement *deinterlace, *vconv, *flip, *vconv2;

        /* DirectShow can express interlaced video, but downstream filters can't
         * necessarily consume it. In particular, the video renderer can't. */
        if (!(deinterlace = create_element("deinterlace", "good")))
            goto out;

        /* decodebin considers many YUV formats to be "raw", but some quartz
         * filters can't handle those. Also, videoflip can't handle all "raw"
         * formats either. Add a videoconvert to swap color spaces. */
        if (!(vconv = create_element("videoconvert", "base")))
            goto out;

        /* GStreamer outputs RGB video top-down, but DirectShow expects bottom-up. */
        if (!(flip = create_element("videoflip", "good")))
            goto out;

        /* videoflip does not support 15 and 16-bit RGB so add a second videoconvert
         * to do the final conversion. */
        if (!(vconv2 = create_element("videoconvert", "base")))
            goto out;

        /* The bin takes ownership of these elements. */
        gst_bin_add(GST_BIN(parser->container), deinterlace);
        gst_element_sync_state_with_parent(deinterlace);
        gst_bin_add(GST_BIN(parser->container), vconv);
        gst_element_sync_state_with_parent(vconv);
        gst_bin_add(GST_BIN(parser->container), flip);
        gst_element_sync_state_with_parent(flip);
        gst_bin_add(GST_BIN(parser->container), vconv2);
        gst_element_sync_state_with_parent(vconv2);

        gst_element_link(deinterlace, vconv);
        gst_element_link(vconv, flip);
        gst_element_link(flip, vconv2);

        stream->post_sink = gst_element_get_static_pad(deinterlace, "sink");
        stream->post_src = gst_element_get_static_pad(vconv2, "src");
        stream->flip = flip;
    }
    else if (!strcmp(name, "audio/x-raw"))
    {
        GstElement *convert;

        /* Currently our dsound can't handle 64-bit formats or all
         * surround-sound configurations. Native dsound can't always handle
         * 64-bit formats either. Add an audioconvert to allow changing bit
         * depth and channel count. */
        if (!(convert = create_element("audioconvert", "base")))
            goto out;

        gst_bin_add(GST_BIN(parser->container), convert);
        gst_element_sync_state_with_parent(convert);

        stream->post_sink = gst_element_get_static_pad(convert, "sink");
        stream->post_src = gst_element_get_static_pad(convert, "src");
    }

    if (stream->post_sink)
    {
        if ((ret = gst_pad_link(pad, stream->post_sink)) < 0)
        {
            GST_ERROR("Failed to link decodebin source pad to post-processing elements, error %s.",
                    gst_pad_link_get_name(ret));
            gst_object_unref(stream->post_sink);
            stream->post_sink = NULL;
            goto out;
        }

        if ((ret = gst_pad_link(stream->post_src, stream->my_sink)) < 0)
        {
            GST_ERROR("Failed to link post-processing elements to our sink pad, error %s.",
                    gst_pad_link_get_name(ret));
            gst_object_unref(stream->post_src);
            stream->post_src = NULL;
            gst_object_unref(stream->post_sink);
            stream->post_sink = NULL;
            goto out;
        }
    }
    else if ((ret = gst_pad_link(pad, stream->my_sink)) < 0)
    {
        GST_ERROR("Failed to link decodebin source pad to our sink pad, error %s.",
                gst_pad_link_get_name(ret));
        goto out;
    }

    gst_pad_set_active(stream->my_sink, 1);
    gst_object_ref(stream->their_src = pad);
out:
    gst_caps_unref(caps);
}

static void pad_removed_cb(GstElement *element, GstPad *pad, gpointer user)
{
    struct wg_parser *parser = user;
    unsigned int i;
    char *name;

    GST_LOG("parser %p, element %p, pad %p.", parser, element, pad);

    for (i = 0; i < parser->stream_count; ++i)
    {
        struct wg_parser_stream *stream = parser->streams[i];

        if (stream->their_src == pad)
        {
            if (stream->post_sink)
                gst_pad_unlink(stream->their_src, stream->post_sink);
            else
                gst_pad_unlink(stream->their_src, stream->my_sink);
            gst_object_unref(stream->their_src);
            stream->their_src = NULL;
            return;
        }
    }

    name = gst_pad_get_name(pad);
    GST_WARNING("No pin matching pad \"%s\" found.", name);
    g_free(name);
}

static GstFlowReturn src_getrange_cb(GstPad *pad, GstObject *parent,
        guint64 offset, guint size, GstBuffer **buffer)
{
    struct wg_parser *parser = gst_pad_get_element_private(pad);
    GstBuffer *new_buffer = NULL;
    GstMapInfo map_info;
    bool ret;

    GST_LOG("pad %p, offset %" G_GINT64_MODIFIER "u, length %u, buffer %p.", pad, offset, size, *buffer);

    if (offset == GST_BUFFER_OFFSET_NONE)
        offset = parser->next_pull_offset;
    parser->next_pull_offset = offset + size;
    if (offset >= parser->file_size)
        return GST_FLOW_EOS;
    if (offset + size >= parser->file_size)
        size = parser->file_size - offset;

    if (!*buffer)
        *buffer = new_buffer = gst_buffer_new_and_alloc(size);

    gst_buffer_map(*buffer, &map_info, GST_MAP_WRITE);

    pthread_mutex_lock(&parser->mutex);

    assert(!parser->read_request.data);
    parser->read_request.data = map_info.data;
    parser->read_request.offset = offset;
    parser->read_request.size = size;
    parser->read_request.done = false;
    pthread_cond_signal(&parser->read_cond);

    /* Note that we don't unblock this wait on GST_EVENT_FLUSH_START. We expect
     * the upstream pin to flush if necessary. We should never be blocked on
     * read_thread() not running. */

    while (!parser->read_request.done)
        pthread_cond_wait(&parser->read_done_cond, &parser->mutex);

    ret = parser->read_request.ret;

    pthread_mutex_unlock(&parser->mutex);

    gst_buffer_unmap(*buffer, &map_info);

    GST_LOG("Request returned %d.", ret);

    if (!ret && new_buffer)
        gst_buffer_unref(new_buffer);

    return ret ? GST_FLOW_OK : GST_FLOW_ERROR;
}

static gboolean src_query_cb(GstPad *pad, GstObject *parent, GstQuery *query)
{
    struct wg_parser *parser = gst_pad_get_element_private(pad);
    GstFormat format;

    GST_LOG("parser %p, type %s.", parser, GST_QUERY_TYPE_NAME(query));

    switch (GST_QUERY_TYPE(query))
    {
        case GST_QUERY_DURATION:
            gst_query_parse_duration(query, &format, NULL);
            if (format == GST_FORMAT_PERCENT)
            {
                gst_query_set_duration(query, GST_FORMAT_PERCENT, GST_FORMAT_PERCENT_MAX);
                return TRUE;
            }
            else if (format == GST_FORMAT_BYTES)
            {
                gst_query_set_duration(query, GST_FORMAT_BYTES, parser->file_size);
                return TRUE;
            }
            return FALSE;

        case GST_QUERY_SEEKING:
            gst_query_parse_seeking (query, &format, NULL, NULL, NULL);
            if (format != GST_FORMAT_BYTES)
            {
                GST_WARNING("Cannot seek using format \"%s\".", gst_format_get_name(format));
                return FALSE;
            }
            gst_query_set_seeking(query, GST_FORMAT_BYTES, 1, 0, parser->file_size);
            return TRUE;

        case GST_QUERY_SCHEDULING:
            gst_query_set_scheduling(query, GST_SCHEDULING_FLAG_SEEKABLE, 1, -1, 0);
            gst_query_add_scheduling_mode(query, GST_PAD_MODE_PUSH);
            gst_query_add_scheduling_mode(query, GST_PAD_MODE_PULL);
            return TRUE;

        default:
            GST_WARNING("Unhandled query type %s.", GST_QUERY_TYPE_NAME(query));
            return FALSE;
    }
}

static void *push_data(void *arg)
{
    struct wg_parser *parser = arg;
    GstBuffer *buffer;
    guint max_size;

    GST_DEBUG("Starting push thread.");

    if (!(buffer = gst_buffer_new_allocate(NULL, 16384, NULL)))
    {
        GST_ERROR("Failed to allocate memory.");
        return NULL;
    }

    max_size = parser->stop_offset ? parser->stop_offset : parser->file_size;

    for (;;)
    {
        ULONG size;
        int ret;

        if (parser->next_offset >= max_size)
            break;
        size = min(16384, max_size - parser->next_offset);

        if ((ret = src_getrange_cb(parser->my_src, NULL, parser->next_offset, size, &buffer)) < 0)
        {
            GST_ERROR("Failed to read data, ret %s.", gst_flow_get_name(ret));
            break;
        }

        parser->next_offset += size;

        buffer->duration = buffer->pts = -1;
        if ((ret = gst_pad_push(parser->my_src, buffer)) < 0)
        {
            GST_ERROR("Failed to push data, ret %s.", gst_flow_get_name(ret));
            break;
        }
    }

    gst_buffer_unref(buffer);

    gst_pad_push_event(parser->my_src, gst_event_new_eos());

    GST_DEBUG("Stopping push thread.");

    return NULL;
}

static gboolean activate_push(GstPad *pad, gboolean activate)
{
    struct wg_parser *parser = gst_pad_get_element_private(pad);

    if (!activate)
    {
        if (parser->push_thread)
        {
            pthread_join(parser->push_thread, NULL);
            parser->push_thread = 0;
        }
    }
    else if (!parser->push_thread)
    {
        int ret;

        if ((ret = pthread_create(&parser->push_thread, NULL, push_data, parser)))
        {
            GST_ERROR("Failed to create push thread: %s", strerror(errno));
            parser->push_thread = 0;
            return FALSE;
        }
    }
    return TRUE;
}

static gboolean src_activate_mode_cb(GstPad *pad, GstObject *parent, GstPadMode mode, gboolean activate)
{
    struct wg_parser *parser = gst_pad_get_element_private(pad);

    GST_DEBUG("%s source pad for parser %p in %s mode.",
            activate ? "Activating" : "Deactivating", parser, gst_pad_mode_get_name(mode));

    switch (mode)
    {
        case GST_PAD_MODE_PULL:
            return TRUE;
        case GST_PAD_MODE_PUSH:
            return activate_push(pad, activate);
        case GST_PAD_MODE_NONE:
            break;
    }
    return FALSE;
}

static GstBusSyncReply bus_handler_cb(GstBus *bus, GstMessage *msg, gpointer user)
{
    struct wg_parser *parser = user;
    gchar *dbg_info = NULL;
    GError *err = NULL;

    GST_DEBUG("parser %p, message type %s.", parser, GST_MESSAGE_TYPE_NAME(msg));

    switch (msg->type)
    {
    case GST_MESSAGE_ERROR:
        gst_message_parse_error(msg, &err, &dbg_info);
        fprintf(stderr, "winegstreamer error: %s: %s\n", GST_OBJECT_NAME(msg->src), err->message);
        fprintf(stderr, "winegstreamer error: %s: %s\n", GST_OBJECT_NAME(msg->src), dbg_info);
        g_error_free(err);
        g_free(dbg_info);
        pthread_mutex_lock(&parser->mutex);
        parser->error = true;
        pthread_mutex_unlock(&parser->mutex);
        pthread_cond_signal(&parser->init_cond);
        break;

    case GST_MESSAGE_WARNING:
        gst_message_parse_warning(msg, &err, &dbg_info);
        fprintf(stderr, "winegstreamer warning: %s: %s\n", GST_OBJECT_NAME(msg->src), err->message);
        fprintf(stderr, "winegstreamer warning: %s: %s\n", GST_OBJECT_NAME(msg->src), dbg_info);
        g_error_free(err);
        g_free(dbg_info);
        break;

    case GST_MESSAGE_DURATION_CHANGED:
        pthread_mutex_lock(&parser->mutex);
        parser->has_duration = true;
        pthread_mutex_unlock(&parser->mutex);
        pthread_cond_signal(&parser->init_cond);
        break;

    default:
        break;
    }
    gst_message_unref(msg);
    return GST_BUS_DROP;
}

static gboolean src_perform_seek(struct wg_parser *parser, GstEvent *event)
{
    BOOL thread = !!parser->push_thread;
    GstSeekType cur_type, stop_type;
    GstFormat seek_format;
    GstEvent *flush_event;
    GstSeekFlags flags;
    gint64 cur, stop;
    guint32 seqnum;
    gdouble rate;

    gst_event_parse_seek(event, &rate, &seek_format, &flags,
                         &cur_type, &cur, &stop_type, &stop);

    if (seek_format != GST_FORMAT_BYTES)
    {
        GST_FIXME("Unhandled format \"%s\".", gst_format_get_name(seek_format));
        return FALSE;
    }

    seqnum = gst_event_get_seqnum(event);

    /* send flush start */
    if (flags & GST_SEEK_FLAG_FLUSH)
    {
        flush_event = gst_event_new_flush_start();
        gst_event_set_seqnum(flush_event, seqnum);
        gst_pad_push_event(parser->my_src, flush_event);
        if (thread)
            gst_pad_set_active(parser->my_src, 1);
    }

    parser->next_offset = parser->start_offset = cur;

    /* and prepare to continue streaming */
    if (flags & GST_SEEK_FLAG_FLUSH)
    {
        flush_event = gst_event_new_flush_stop(TRUE);
        gst_event_set_seqnum(flush_event, seqnum);
        gst_pad_push_event(parser->my_src, flush_event);
        if (thread)
            gst_pad_set_active(parser->my_src, 1);
    }

    return TRUE;
}

static gboolean src_event_cb(GstPad *pad, GstObject *parent, GstEvent *event)
{
    struct wg_parser *parser = gst_pad_get_element_private(pad);
    gboolean ret = TRUE;

    GST_LOG("parser %p, type \"%s\".", parser, GST_EVENT_TYPE_NAME(event));

    switch (event->type)
    {
        case GST_EVENT_SEEK:
            ret = src_perform_seek(parser, event);
            break;

        case GST_EVENT_FLUSH_START:
        case GST_EVENT_FLUSH_STOP:
        case GST_EVENT_QOS:
        case GST_EVENT_RECONFIGURE:
            break;

        default:
            GST_WARNING("Ignoring \"%s\" event.", GST_EVENT_TYPE_NAME(event));
            ret = FALSE;
            break;
    }
    gst_event_unref(event);
    return ret;
}

static HRESULT CDECL wg_parser_connect(struct wg_parser *parser, uint64_t file_size)
{
    GstStaticPadTemplate src_template = GST_STATIC_PAD_TEMPLATE("quartz_src",
            GST_PAD_SRC, GST_PAD_ALWAYS, GST_STATIC_CAPS_ANY);
    unsigned int i;

    parser->file_size = file_size;
    parser->sink_connected = true;

    if (!parser->bus)
    {
        parser->bus = gst_bus_new();
        gst_bus_set_sync_handler(parser->bus, bus_handler_cb, parser, NULL);
    }

    parser->container = gst_bin_new(NULL);
    gst_element_set_bus(parser->container, parser->bus);

    parser->my_src = gst_pad_new_from_static_template(&src_template, "quartz-src");
    gst_pad_set_getrange_function(parser->my_src, src_getrange_cb);
    gst_pad_set_query_function(parser->my_src, src_query_cb);
    gst_pad_set_activatemode_function(parser->my_src, src_activate_mode_cb);
    gst_pad_set_event_function(parser->my_src, src_event_cb);
    gst_pad_set_element_private(parser->my_src, parser);

    parser->start_offset = parser->next_offset = parser->stop_offset = 0;
    parser->next_pull_offset = 0;

    if (!parser->init_gst(parser))
        return E_FAIL;

    pthread_mutex_lock(&parser->mutex);

    for (i = 0; i < parser->stream_count; ++i)
    {
        struct wg_parser_stream *stream = parser->streams[i];
        gint64 duration;

        while (!stream->has_caps && !parser->error)
            pthread_cond_wait(&parser->init_cond, &parser->mutex);

        /* GStreamer doesn't actually provide any guarantees about when duration
         * is available, even for seekable streams. It's basically built for
         * applications that don't care, e.g. movie players that can display
         * a duration once it's available, and update it visually if a better
         * estimate is found. This doesn't really match well with DirectShow or
         * Media Foundation, which both expect duration to be available
         * immediately on connecting, so we have to use some complex heuristics
         * to try to actually get a usable duration.
         *
         * Some elements (avidemux, wavparse, qtdemux) record duration almost
         * immediately, before fixing caps. Such elements don't send
         * duration-changed messages. Therefore always try querying duration
         * after caps have been found.
         *
         * Some elements (mpegaudioparse) send duration-changed. In the case of
         * a mp3 stream without seek tables it will not be sent immediately, but
         * only after enough frames have been parsed to form an estimate. They
         * may send it multiple times with increasingly accurate estimates, but
         * unfortunately we have no way of knowing whether another estimate will
         * be sent, so we always take the first one. We assume that if the
         * duration is not immediately available then the element will always
         * send duration-changed.
         */

        for (;;)
        {
            if (parser->error)
            {
                pthread_mutex_unlock(&parser->mutex);
                return E_FAIL;
            }
            if (gst_pad_query_duration(stream->their_src, GST_FORMAT_TIME, &duration))
            {
                stream->duration = duration / 100;
                break;
            }

            if (stream->eos)
            {
                stream->duration = 0;
                GST_WARNING("Failed to query duration.\n");
                break;
            }

            /* Elements based on GstBaseParse send duration-changed before
             * actually updating the duration in GStreamer versions prior
             * to 1.17.1. See <gstreamer.git:d28e0b4147fe7073b2>. So after
             * receiving duration-changed we have to continue polling until
             * the query succeeds. */
            if (parser->has_duration)
            {
                pthread_mutex_unlock(&parser->mutex);
                g_usleep(10000);
                pthread_mutex_lock(&parser->mutex);
            }
            else
            {
                pthread_cond_wait(&parser->init_cond, &parser->mutex);
            }
        }
    }

    pthread_mutex_unlock(&parser->mutex);

    parser->next_offset = 0;
    return S_OK;
}

static void free_stream(struct wg_parser_stream *stream)
{
    if (stream->their_src)
    {
        if (stream->post_sink)
        {
            gst_pad_unlink(stream->their_src, stream->post_sink);
            gst_pad_unlink(stream->post_src, stream->my_sink);
            gst_object_unref(stream->post_src);
            gst_object_unref(stream->post_sink);
            stream->post_src = stream->post_sink = NULL;
        }
        else
            gst_pad_unlink(stream->their_src, stream->my_sink);
        gst_object_unref(stream->their_src);
    }
    gst_object_unref(stream->my_sink);

    pthread_cond_destroy(&stream->event_cond);
    pthread_cond_destroy(&stream->event_empty_cond);

    free(stream);
}

static void CDECL wg_parser_disconnect(struct wg_parser *parser)
{
    unsigned int i;

    /* Unblock all of our streams. */
    pthread_mutex_lock(&parser->mutex);
    for (i = 0; i < parser->stream_count; ++i)
    {
        parser->streams[i]->flushing = true;
        pthread_cond_signal(&parser->streams[i]->event_empty_cond);
    }
    pthread_mutex_unlock(&parser->mutex);

    gst_element_set_state(parser->container, GST_STATE_NULL);
    gst_pad_unlink(parser->my_src, parser->their_sink);
    gst_object_unref(parser->my_src);
    gst_object_unref(parser->their_sink);
    parser->my_src = parser->their_sink = NULL;

    pthread_mutex_lock(&parser->mutex);
    parser->sink_connected = false;
    pthread_mutex_unlock(&parser->mutex);
    pthread_cond_signal(&parser->read_cond);

    for (i = 0; i < parser->stream_count; ++i)
        free_stream(parser->streams[i]);

    parser->stream_count = 0;
    free(parser->streams);
    parser->streams = NULL;

    gst_element_set_bus(parser->container, NULL);
    gst_object_unref(parser->container);
    parser->container = NULL;
}

static BOOL decodebin_parser_init_gst(struct wg_parser *parser)
{
    GstElement *element;
    int ret;

    if (!(element = create_element("decodebin", "base")))
        return FALSE;

    gst_bin_add(GST_BIN(parser->container), element);
    parser->decodebin = element;

    g_signal_connect(element, "pad-added", G_CALLBACK(pad_added_cb), parser);
    g_signal_connect(element, "pad-removed", G_CALLBACK(pad_removed_cb), parser);
    g_signal_connect(element, "autoplug-select", G_CALLBACK(autoplug_select_cb), parser);
    g_signal_connect(element, "no-more-pads", G_CALLBACK(no_more_pads_cb), parser);

    parser->their_sink = gst_element_get_static_pad(element, "sink");

    pthread_mutex_lock(&parser->mutex);
    parser->no_more_pads = parser->error = false;
    pthread_mutex_unlock(&parser->mutex);

    if ((ret = gst_pad_link(parser->my_src, parser->their_sink)) < 0)
    {
        GST_ERROR("Failed to link pads, error %d.\n", ret);
        return FALSE;
    }

    gst_element_set_state(parser->container, GST_STATE_PAUSED);
    ret = gst_element_get_state(parser->container, NULL, NULL, -1);
    if (ret == GST_STATE_CHANGE_FAILURE)
    {
        GST_ERROR("Failed to play stream.\n");
        return FALSE;
    }

    pthread_mutex_lock(&parser->mutex);
    while (!parser->no_more_pads && !parser->error)
        pthread_cond_wait(&parser->init_cond, &parser->mutex);
    if (parser->error)
    {
        pthread_mutex_unlock(&parser->mutex);
        return FALSE;
    }
    pthread_mutex_unlock(&parser->mutex);

    return TRUE;
}

static BOOL avi_parser_init_gst(struct wg_parser *parser)
{
    GstElement *element;
    int ret;

    if (!(element = create_element("avidemux", "good")))
        return FALSE;

    gst_bin_add(GST_BIN(parser->container), element);

    g_signal_connect(element, "pad-added", G_CALLBACK(pad_added_cb), parser);
    g_signal_connect(element, "pad-removed", G_CALLBACK(pad_removed_cb), parser);
    g_signal_connect(element, "no-more-pads", G_CALLBACK(no_more_pads_cb), parser);

    parser->their_sink = gst_element_get_static_pad(element, "sink");

    pthread_mutex_lock(&parser->mutex);
    parser->no_more_pads = parser->error = false;
    pthread_mutex_unlock(&parser->mutex);

    if ((ret = gst_pad_link(parser->my_src, parser->their_sink)) < 0)
    {
        GST_ERROR("Failed to link pads, error %d.\n", ret);
        return FALSE;
    }

    gst_element_set_state(parser->container, GST_STATE_PAUSED);
    ret = gst_element_get_state(parser->container, NULL, NULL, -1);
    if (ret == GST_STATE_CHANGE_FAILURE)
    {
        GST_ERROR("Failed to play stream.\n");
        return FALSE;
    }

    pthread_mutex_lock(&parser->mutex);
    while (!parser->no_more_pads && !parser->error)
        pthread_cond_wait(&parser->init_cond, &parser->mutex);
    if (parser->error)
    {
        pthread_mutex_unlock(&parser->mutex);
        return FALSE;
    }
    pthread_mutex_unlock(&parser->mutex);

    return TRUE;
}

static BOOL mpeg_audio_parser_init_gst(struct wg_parser *parser)
{
    struct wg_parser_stream *stream;
    GstElement *element;
    int ret;

    if (!(element = create_element("mpegaudioparse", "good")))
        return FALSE;

    gst_bin_add(GST_BIN(parser->container), element);

    parser->their_sink = gst_element_get_static_pad(element, "sink");
    if ((ret = gst_pad_link(parser->my_src, parser->their_sink)) < 0)
    {
        GST_ERROR("Failed to link sink pads, error %d.\n", ret);
        return FALSE;
    }

    if (!(stream = create_stream(parser)))
        return FALSE;

    gst_object_ref(stream->their_src = gst_element_get_static_pad(element, "src"));
    if ((ret = gst_pad_link(stream->their_src, stream->my_sink)) < 0)
    {
        GST_ERROR("Failed to link source pads, error %d.\n", ret);
        return FALSE;
    }

    gst_pad_set_active(stream->my_sink, 1);
    gst_element_set_state(parser->container, GST_STATE_PAUSED);
    ret = gst_element_get_state(parser->container, NULL, NULL, -1);
    if (ret == GST_STATE_CHANGE_FAILURE)
    {
        GST_ERROR("Failed to play stream.\n");
        return FALSE;
    }

    return TRUE;
}

static BOOL wave_parser_init_gst(struct wg_parser *parser)
{
    struct wg_parser_stream *stream;
    GstElement *element;
    int ret;

    if (!(element = create_element("wavparse", "good")))
        return FALSE;

    gst_bin_add(GST_BIN(parser->container), element);

    parser->their_sink = gst_element_get_static_pad(element, "sink");
    if ((ret = gst_pad_link(parser->my_src, parser->their_sink)) < 0)
    {
        GST_ERROR("Failed to link sink pads, error %d.\n", ret);
        return FALSE;
    }

    if (!(stream = create_stream(parser)))
        return FALSE;

    stream->their_src = gst_element_get_static_pad(element, "src");
    gst_object_ref(stream->their_src);
    if ((ret = gst_pad_link(stream->their_src, stream->my_sink)) < 0)
    {
        GST_ERROR("Failed to link source pads, error %d.\n", ret);
        return FALSE;
    }

    gst_pad_set_active(stream->my_sink, 1);
    gst_element_set_state(parser->container, GST_STATE_PAUSED);
    ret = gst_element_get_state(parser->container, NULL, NULL, -1);
    if (ret == GST_STATE_CHANGE_FAILURE)
    {
        GST_ERROR("Failed to play stream.\n");
        return FALSE;
    }

    return TRUE;
}

static struct wg_parser *wg_parser_create(void)
{
    struct wg_parser *parser;

    if (!(parser = calloc(1, sizeof(*parser))))
        return NULL;

    pthread_mutex_init(&parser->mutex, NULL);
    pthread_cond_init(&parser->init_cond, NULL);
    pthread_cond_init(&parser->read_cond, NULL);
    pthread_cond_init(&parser->read_done_cond, NULL);
    parser->flushing = true;

    GST_DEBUG("Created winegstreamer parser %p.\n", parser);
    return parser;
}

static struct wg_parser * CDECL wg_decodebin_parser_create(void)
{
    struct wg_parser *parser;

    if ((parser = wg_parser_create()))
        parser->init_gst = decodebin_parser_init_gst;
    return parser;
}

static struct wg_parser * CDECL wg_avi_parser_create(void)
{
    struct wg_parser *parser;

    if ((parser = wg_parser_create()))
        parser->init_gst = avi_parser_init_gst;
    return parser;
}

static struct wg_parser * CDECL wg_mpeg_audio_parser_create(void)
{
    struct wg_parser *parser;

    if ((parser = wg_parser_create()))
        parser->init_gst = mpeg_audio_parser_init_gst;
    return parser;
}

static struct wg_parser * CDECL wg_wave_parser_create(void)
{
    struct wg_parser *parser;

    if ((parser = wg_parser_create()))
        parser->init_gst = wave_parser_init_gst;
    return parser;
}

static void CDECL wg_parser_destroy(struct wg_parser *parser)
{
    if (parser->bus)
    {
        gst_bus_set_sync_handler(parser->bus, NULL, NULL, NULL);
        gst_object_unref(parser->bus);
    }

    pthread_mutex_destroy(&parser->mutex);
    pthread_cond_destroy(&parser->init_cond);
    pthread_cond_destroy(&parser->read_cond);
    pthread_cond_destroy(&parser->read_done_cond);

    free(parser);
}

static const struct unix_funcs funcs =
{
    wg_decodebin_parser_create,
    wg_avi_parser_create,
    wg_mpeg_audio_parser_create,
    wg_wave_parser_create,
    wg_parser_destroy,

    wg_parser_connect,
    wg_parser_disconnect,

    wg_parser_begin_flush,
    wg_parser_end_flush,

    wg_parser_get_read_request,
    wg_parser_complete_read_request,

    wg_parser_set_unlimited_buffering,

    wg_parser_get_stream_count,
    wg_parser_get_stream,

    wg_parser_stream_get_preferred_format,
    wg_parser_stream_enable,
    wg_parser_stream_disable,

    wg_parser_stream_get_event,
    wg_parser_stream_copy_buffer,
    wg_parser_stream_release_buffer,
    wg_parser_stream_notify_qos,

    wg_parser_stream_get_duration,
    wg_parser_stream_seek,
};

NTSTATUS CDECL __wine_init_unix_lib(HMODULE module, DWORD reason, const void *ptr_in, void *ptr_out)
{
    if (reason == DLL_PROCESS_ATTACH)
    {
        char arg0[] = "wine";
        char arg1[] = "--gst-disable-registry-fork";
        char *args[] = {arg0, arg1, NULL};
        int argc = ARRAY_SIZE(args) - 1;
        char **argv = args;
        GError *err;

        if (!gst_init_check(&argc, &argv, &err))
        {
            fprintf(stderr, "winegstreamer: failed to initialize GStreamer: %s\n", debugstr_a(err->message));
            g_error_free(err);
            return STATUS_UNSUCCESSFUL;
        }

        GST_DEBUG_CATEGORY_INIT(wine, "WINE", GST_DEBUG_FG_RED, "Wine GStreamer support");

        GST_INFO("GStreamer library version %s; wine built with %d.%d.%d.\n",
                gst_version_string(), GST_VERSION_MAJOR, GST_VERSION_MINOR, GST_VERSION_MICRO);

        *(const struct unix_funcs **)ptr_out = &funcs;
    }
    return STATUS_SUCCESS;
}