Aegisub/libaegisub/common/vfr.cpp

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// Copyright (c) 2010, Thomas Goyne <plorkyeran@aegisub.org>
//
// Permission to use, copy, modify, and distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
/// @file vfr.cpp
/// @brief Framerate handling of all sorts
/// @ingroup libaegisub video_input
#include "libaegisub/vfr.h"
#include "libaegisub/charset.h"
#include "libaegisub/io.h"
#include "libaegisub/line_iterator.h"
#include <algorithm>
#include <boost/interprocess/streams/bufferstream.hpp>
#include <boost/range/algorithm.hpp>
#include <cmath>
#include <functional>
#include <iterator>
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namespace {
static const int64_t default_denominator = 1000000000;
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using agi::line_iterator;
using namespace agi::vfr;
/// @brief Verify that timecodes monotonically increase
/// @param timecodes List of timecodes to check
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void validate_timecodes(std::vector<int> const& timecodes) {
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if (timecodes.size() <= 1)
throw InvalidFramerate("Must have at least two timecodes to do anything useful");
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if (!is_sorted(timecodes.begin(), timecodes.end()))
throw InvalidFramerate("Timecodes are out of order");
if (timecodes.front() == timecodes.back())
throw InvalidFramerate("Timecodes are all identical");
}
/// @brief Shift timecodes so that frame 0 starts at time 0
/// @param timecodes List of timecodes to normalize
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void normalize_timecodes(std::vector<int> &timecodes) {
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if (int front = timecodes.front())
boost::for_each(timecodes, [=](int &tc) { tc -= front; });
}
// A "start,end,fps" line in a v1 timecode file
struct TimecodeRange {
int start;
int end;
double fps;
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bool operator<(TimecodeRange const& cmp) const { return start < cmp.start; }
};
/// @brief Parse a single line of a v1 timecode file
/// @param str Line to parse
/// @return The line in TimecodeRange form, or TimecodeRange() if it's a comment
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TimecodeRange v1_parse_line(std::string const& str) {
if (str.empty() || str[0] == '#') return TimecodeRange();
boost::interprocess::ibufferstream ss(str.data(), str.size());
TimecodeRange range;
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char comma1 = 0, comma2 = 0;
ss >> range.start >> comma1 >> range.end >> comma2 >> range.fps;
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if (ss.fail() || comma1 != ',' || comma2 != ',' || !ss.eof())
throw MalformedLine(str);
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if (range.start < 0 || range.end < 0)
throw InvalidFramerate("Cannot specify frame rate for negative frames.");
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if (range.end < range.start)
throw InvalidFramerate("End frame must be greater than or equal to start frame");
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if (range.fps <= 0.)
throw InvalidFramerate("FPS must be greater than zero");
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if (range.fps > 1000.)
// This is our limitation, not mkvmerge's
// mkvmerge uses nanoseconds internally
throw InvalidFramerate("FPS must be at most 1000");
return range;
}
/// @brief Parse a v1 timecode file
/// @param file Iterator of lines in the file
/// @param line Header of file with assumed fps
/// @param[out] timecodes Vector filled with frame start times
/// @param[out] last Unrounded time of the last frame
/// @return Assumed fps times one million
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int64_t v1_parse(line_iterator<std::string> file, std::string line, std::vector<int> &timecodes, int64_t &last) {
double fps = atof(line.substr(7).c_str());
if (fps <= 0.) throw InvalidFramerate("Assumed FPS must be greater than zero");
if (fps > 1000.) throw InvalidFramerate("Assumed FPS must not be greater than 1000");
std::vector<TimecodeRange> ranges;
for (auto const& line : file) {
auto range = v1_parse_line(line);
if (range.fps != 0)
ranges.push_back(range);
}
std::sort(begin(ranges), end(ranges));
if (!ranges.empty())
timecodes.reserve(ranges.back().end + 2);
double time = 0.;
int frame = 0;
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for (auto const& range : ranges) {
if (frame > range.start) {
// mkvmerge allows overlapping timecode ranges, but does completely
// broken things with them
throw InvalidFramerate("Override ranges must not overlap");
}
for (; frame < range.start; ++frame) {
timecodes.push_back(int(time + .5));
time += 1000. / fps;
}
for (; frame <= range.end; ++frame) {
timecodes.push_back(int(time + .5));
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time += 1000. / range.fps;
}
}
timecodes.push_back(int(time + .5));
last = int64_t(time * fps * default_denominator);
return int64_t(fps * default_denominator);
}
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}
namespace agi { namespace vfr {
Framerate::Framerate(double fps)
: denominator(default_denominator)
, numerator(int64_t(fps * denominator))
{
if (fps < 0.) throw InvalidFramerate("FPS must be greater than zero");
if (fps > 1000.) throw InvalidFramerate("FPS must not be greater than 1000");
timecodes.push_back(0);
}
Framerate::Framerate(int64_t numerator, int64_t denominator, bool drop)
: denominator(denominator)
, numerator(numerator)
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, drop(drop && denominator != 0 && numerator % denominator != 0)
{
if (numerator <= 0 || denominator <= 0)
throw InvalidFramerate("Numerator and denominator must both be greater than zero");
if (numerator / denominator > 1000) throw InvalidFramerate("FPS must not be greater than 1000");
timecodes.push_back(0);
}
void Framerate::SetFromTimecodes() {
validate_timecodes(timecodes);
normalize_timecodes(timecodes);
denominator = default_denominator;
numerator = (timecodes.size() - 1) * denominator * 1000 / timecodes.back();
last = (timecodes.size() - 1) * denominator * 1000;
}
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Framerate::Framerate(std::vector<int> timecodes)
: timecodes(std::move(timecodes))
{
SetFromTimecodes();
}
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Framerate::Framerate(std::initializer_list<int> timecodes)
: timecodes(timecodes)
{
SetFromTimecodes();
}
Framerate::Framerate(fs::path const& filename)
: denominator(default_denominator)
{
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auto file = agi::io::Open(filename);
auto encoding = agi::charset::Detect(filename);
auto line = *line_iterator<std::string>(*file, encoding);
if (line == "# timecode format v2") {
copy(line_iterator<int>(*file, encoding), line_iterator<int>(), back_inserter(timecodes));
SetFromTimecodes();
return;
}
if (line == "# timecode format v1" || line.substr(0, 7) == "Assume ") {
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if (line[0] == '#')
line = *line_iterator<std::string>(*file, encoding);
numerator = v1_parse(line_iterator<std::string>(*file, encoding), line, timecodes, last);
return;
}
throw UnknownFormat(line);
}
void Framerate::Save(fs::path const& filename, int length) const {
agi::io::Save file(filename);
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auto &out = file.Get();
out << "# timecode format v2\n";
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boost::copy(timecodes, std::ostream_iterator<int>(out, "\n"));
for (int written = (int)timecodes.size(); written < length; ++written)
out << TimeAtFrame(written) << std::endl;
}
int Framerate::FrameAtTime(int ms, Time type) const {
// With X ms per frame, this should return 0 for:
// EXACT: [0, X - 1]
// START: [1 - X , 0]
// END: [1, X]
// There are two properties we take advantage of here:
// 1. START and END's ranges are adjacent, meaning doing the calculations
// for END and adding one gives us START
// 2. END is EXACT plus one ms, meaning we can subtract one ms to get EXACT
// Combining these allows us to easily calculate START and END in terms of
// EXACT
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if (type == START)
return FrameAtTime(ms - 1) + 1;
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if (type == END)
return FrameAtTime(ms - 1);
if (ms < 0)
return int((ms * numerator / denominator - 999) / 1000);
if (ms > timecodes.back())
return int((ms * numerator - numerator / 2 - last + numerator - 1) / denominator / 1000) + (int)timecodes.size() - 1;
return (int)distance(lower_bound(timecodes.rbegin(), timecodes.rend(), ms, std::greater<int>()), timecodes.rend()) - 1;
}
int Framerate::TimeAtFrame(int frame, Time type) const {
if (type == START) {
int prev = TimeAtFrame(frame - 1);
int cur = TimeAtFrame(frame);
// + 1 as these need to round up for the case of two frames 1 ms apart
return prev + (cur - prev + 1) / 2;
}
if (type == END) {
int cur = TimeAtFrame(frame);
int next = TimeAtFrame(frame + 1);
return cur + (next - cur + 1) / 2;
}
if (frame < 0)
return (int)(frame * denominator * 1000 / numerator);
if (frame >= (signed)timecodes.size()) {
int64_t frames_past_end = frame - (int)timecodes.size() + 1;
return int((frames_past_end * 1000 * denominator + last + numerator / 2) / numerator);
}
return timecodes[frame];
}
void Framerate::SmpteAtFrame(int frame, int *h, int *m, int *s, int *f) const {
frame = std::max(frame, 0);
int ifps = (int)ceil(FPS());
if (drop && denominator == 1001 && numerator % 30000 == 0) {
// NTSC skips the first two frames of every minute except for multiples
// of ten. For multiples of NTSC, simply multiplying the number of
// frames skips seems like the most sensible option.
const int drop_factor = int(numerator / 30000);
const int one_minute = 60 * 30 * drop_factor - drop_factor * 2;
const int ten_minutes = 60 * 10 * 30 * drop_factor - drop_factor * 18;
const int ten_minute_groups = frame / ten_minutes;
const int last_ten_minutes = frame % ten_minutes;
frame += ten_minute_groups * 18 * drop_factor;
frame += (last_ten_minutes - 2 * drop_factor) / one_minute * 2 * drop_factor;
}
// Non-integral frame rates other than NTSC aren't supported by SMPTE
// timecodes, but the user has asked for it so just give something that
// resembles a valid timecode which is no more than half a frame off
// wallclock time
else if (drop && ifps != FPS()) {
frame = int(frame / FPS() * ifps + 0.5);
}
*h = frame / (ifps * 60 * 60);
*m = (frame / (ifps * 60)) % 60;
*s = (frame / ifps) % 60;
*f = frame % ifps;
}
void Framerate::SmpteAtTime(int ms, int *h, int *m, int *s, int *f) const {
SmpteAtFrame(FrameAtTime(ms), h, m, s, f);
}
int Framerate::FrameAtSmpte(int h, int m, int s, int f) const {
int ifps = (int)ceil(FPS());
if (drop && denominator == 1001 && numerator % 30000 == 0) {
const int drop_factor = int(numerator / 30000);
const int one_minute = 60 * 30 * drop_factor - drop_factor * 2;
const int ten_minutes = 60 * 10 * 30 * drop_factor - drop_factor * 18;
const int ten_m = m / 10;
m = m % 10;
// The specified frame doesn't actually exist so skip forward to the
// next frame that does
if (m != 0 && s == 0 && f < 2 * drop_factor)
f = 2 * drop_factor;
return h * ten_minutes * 6 + ten_m * ten_minutes + m * one_minute + s * ifps + f;
}
else if (drop && ifps != FPS()) {
int frame = (h * 60 * 60 + m * 60 + s) * ifps + f;
return int((double)frame / ifps * FPS() + 0.5);
}
return (h * 60 * 60 + m * 60 + s) * ifps + f;
}
int Framerate::TimeAtSmpte(int h, int m, int s, int f) const {
return TimeAtFrame(FrameAtSmpte(h, m, s, f));
}
} }