Aegisub/aegisub/libaegisub/common/vfr.cpp

320 lines
9.9 KiB
C++

// 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.
//
// $Id$
/// @file vfr.cpp
/// @brief Framerate handling of all sorts
/// @ingroup libaegisub video_input
#include "libaegisub/vfr.h"
#ifndef LAGI_PRE
#include <algorithm>
#include <cmath>
#include <functional>
#include <iterator>
#include <list>
#include <numeric>
#endif
#include "libaegisub/charset.h"
#include "libaegisub/io.h"
#include "libaegisub/line_iterator.h"
#include "libaegisub/scoped_ptr.h"
namespace std {
template<> void swap(agi::vfr::Framerate &lft, agi::vfr::Framerate &rgt) {
lft.swap(rgt);
}
}
static const int64_t default_denominator = 1000000000;
namespace agi {
namespace vfr {
static int is_increasing(int prev, int cur) {
if (prev >= cur) {
throw UnorderedTimecodes("Timecodes are out of order or too close together");
}
return cur;
}
/// @brief Verify that timecodes monotonically increase
/// @param timecodes List of timecodes to check
static void validate_timecodes(std::vector<int> const& timecodes) {
if (timecodes.size() <= 1) {
throw TooFewTimecodes("Must have at least two timecodes to do anything useful");
}
std::accumulate(timecodes.begin()+1, timecodes.end(), timecodes.front(), is_increasing);
}
/// @brief Shift timecodes so that frame 0 starts at time 0
/// @param timecodes List of timecodes to normalize
static void normalize_timecodes(std::vector<int> &timecodes) {
if (int front = timecodes.front()) {
std::transform(timecodes.begin(), timecodes.end(), timecodes.begin(), std::bind2nd(std::minus<int>(), front));
}
}
// A "start,end,fps" line in a v1 timecode file
struct TimecodeRange {
int start;
int end;
double fps;
bool operator<(TimecodeRange cmp) {
return start < cmp.start;
}
TimecodeRange() : fps(0.) { }
};
/// @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
static TimecodeRange v1_parse_line(std::string const& str) {
if (str.empty() || str[0] == '#') return TimecodeRange();
std::istringstream ss(str);
TimecodeRange range;
char comma1, comma2;
ss >> range.start >> comma1 >> range.end >> comma2 >> range.fps;
if (ss.fail() || comma1 != ',' || comma2 != ',' || !ss.eof()) {
throw MalformedLine(str);
}
if (range.start < 0 || range.end < 0) {
throw UnorderedTimecodes("Cannot specify frame rate for negative frames.");
}
if (range.end < range.start) {
throw UnorderedTimecodes("End frame must be greater than or equal to start frame");
}
if (range.fps <= 0.) {
throw BadFPS("FPS must be greater than zero");
}
if (range.fps > 1000.) {
// This is our limitation, not mkvmerge's
// mkvmerge uses nanoseconds internally
throw BadFPS("FPS must be at most 1000");
}
return range;
}
/// @brief Is the timecode range a comment line?
static bool v1_invalid_timecode(TimecodeRange const& range) {
return range.fps == 0.;
}
/// @brief Generate override ranges for all frames with assumed fpses
/// @param ranges List with ranges which is mutated
/// @param fps Assumed fps to use for gaps
static void v1_fill_range_gaps(std::list<TimecodeRange> &ranges, double fps) {
// Range for frames between start and first override
if (ranges.empty() || ranges.front().start > 0) {
TimecodeRange range;
range.fps = fps;
range.start = 0;
range.end = ranges.empty() ? 0 : ranges.front().start - 1;
ranges.push_front(range);
}
std::list<TimecodeRange>::iterator cur = ++ranges.begin();
std::list<TimecodeRange>::iterator prev = ranges.begin();
for (; cur != ranges.end(); ++cur, ++prev) {
if (prev->end >= cur->start) {
// mkvmerge allows overlapping timecode ranges, but does completely
// broken things with them
throw UnorderedTimecodes("Override ranges must not overlap");
}
if (prev->end + 1 < cur->start) {
TimecodeRange range;
range.fps = fps;
range.start = prev->end + 1;
range.end = cur->start - 1;
ranges.insert(cur, range);
++prev;
}
}
}
/// @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
static int64_t v1_parse(line_iterator<std::string> file, std::string line, std::vector<int> &timecodes, int64_t &last) {
using namespace std;
double fps = atof(line.substr(7).c_str());
if (fps <= 0.) throw BadFPS("Assumed FPS must be greater than zero");
if (fps > 1000.) throw BadFPS("Assumed FPS must not be greater than 1000");
list<TimecodeRange> ranges;
transform(file, line_iterator<string>(), back_inserter(ranges), v1_parse_line);
ranges.erase(remove_if(ranges.begin(), ranges.end(), v1_invalid_timecode), ranges.end());
ranges.sort();
v1_fill_range_gaps(ranges, fps);
timecodes.reserve(ranges.back().end);
double time = 0.;
for (list<TimecodeRange>::iterator cur = ranges.begin(); cur != ranges.end(); ++cur) {
for (int frame = cur->start; frame <= cur->end; frame++) {
timecodes.push_back(int(time + .5));
time += 1000. / cur->fps;
}
}
timecodes.push_back(int(time + .5));
last = int64_t(time * fps * default_denominator);
return int64_t(fps * default_denominator);
}
Framerate::Framerate(double fps)
: denominator(default_denominator)
, numerator(int64_t(fps * denominator))
, last(0)
{
if (fps < 0.) throw BadFPS("FPS must be greater than zero");
if (fps > 1000.) throw BadFPS("FPS must not be greater than 1000");
timecodes.push_back(0);
}
Framerate::Framerate(int64_t numerator, int64_t denominator)
: denominator(denominator)
, numerator(numerator)
, last(0)
{
if (numerator <= 0 || denominator <= 0)
throw BadFPS("Numerator and denominator must both be greater than zero");
if (numerator / denominator > 1000) throw BadFPS("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;
}
Framerate::Framerate(std::vector<int> const& timecodes)
: timecodes(timecodes)
{
SetFromTimecodes();
}
void Framerate::swap(Framerate &right) throw() {
using std::swap;
swap(numerator, right.numerator);
swap(denominator, right.denominator);
swap(last, right.last);
swap(timecodes, right.timecodes);
}
Framerate &Framerate::operator=(double fps) {
return *this = Framerate(fps);
}
Framerate::Framerate(std::string const& filename)
: denominator(default_denominator)
, numerator(0)
{
using namespace std;
scoped_ptr<ifstream> file(agi::io::Open(filename));
string encoding = agi::charset::Detect(filename);
string line = *line_iterator<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 ") {
if (line[0] == '#') {
line = *line_iterator<string>(*file, encoding);
}
numerator = v1_parse(line_iterator<string>(*file, encoding), line, timecodes, last);
return;
}
throw UnknownFormat(line);
}
void Framerate::Save(std::string const& filename, int length) const {
agi::io::Save file(filename);
std::ofstream &out = file.Get();
out << "# timecode format v2\n";
std::copy(timecodes.begin(), timecodes.end(), 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
if (type == START) {
return FrameAtTime(ms - 1) + 1;
}
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 - last + denominator - 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];
}
}
}