Aegisub/aegisub/libffms/src/core/fflavfvideo.cpp

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// Copyright (c) 2007-2009 Fredrik Mellbin
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
#include "ffvideosource.h"
void FFLAVFVideo::Free(bool CloseCodec) {
if (CloseCodec)
avcodec_close(CodecContext);
av_close_input_file(FormatContext);
}
FFLAVFVideo::FFLAVFVideo(const char *SourceFile, int Track, FFIndex *Index,
const char *PP, int Threads, int SeekMode, char *ErrorMsg, unsigned MsgSize)
: FFVideo(SourceFile, Index, ErrorMsg, MsgSize) {
FormatContext = NULL;
AVCodec *Codec = NULL;
this->SeekMode = SeekMode;
VideoTrack = Track;
Frames = (*Index)[VideoTrack];
if (Frames.size() == 0) {
snprintf(ErrorMsg, MsgSize, "Video track contains no frames");
throw ErrorMsg;
}
if (av_open_input_file(&FormatContext, SourceFile, NULL, 0, NULL) != 0) {
snprintf(ErrorMsg, MsgSize, "Couldn't open '%s'", SourceFile);
throw ErrorMsg;
}
if (av_find_stream_info(FormatContext) < 0) {
Free(false);
snprintf(ErrorMsg, MsgSize, "Couldn't find stream information");
throw ErrorMsg;
}
if (SeekMode >= 0 && av_seek_frame(FormatContext, VideoTrack, Frames[0].DTS, AVSEEK_FLAG_BACKWARD) < 0) {
Free(false);
snprintf(ErrorMsg, MsgSize, "Video track is unseekable");
throw ErrorMsg;
}
CodecContext = FormatContext->streams[VideoTrack]->codec;
CodecContext->thread_count = Threads;
Codec = avcodec_find_decoder(CodecContext->codec_id);
if (Codec == NULL) {
Free(false);
snprintf(ErrorMsg, MsgSize, "Video codec not found");
throw ErrorMsg;
}
if (avcodec_open(CodecContext, Codec) < 0) {
Free(false);
snprintf(ErrorMsg, MsgSize, "Could not open video codec");
throw ErrorMsg;
}
// Always try to decode a frame to make sure all required parameters are known
int64_t Dummy;
if (DecodeNextFrame(&Dummy, ErrorMsg, MsgSize)) {
Free(true);
throw ErrorMsg;
}
//VP.image_type = VideoInfo::IT_TFF;
VP.Width = CodecContext->width;
VP.Height = CodecContext->height;
VP.FPSDenominator = FormatContext->streams[VideoTrack]->time_base.num;
VP.FPSNumerator = FormatContext->streams[VideoTrack]->time_base.den;
VP.RFFDenominator = CodecContext->time_base.num;
VP.RFFNumerator = CodecContext->time_base.den;
VP.NumFrames = Frames.size();
VP.VPixelFormat = CodecContext->pix_fmt;
VP.FirstTime = ((Frames.front().DTS * Frames.TB.Num) / (double)Frames.TB.Den) / 1000;
VP.LastTime = ((Frames.back().DTS * Frames.TB.Num) / (double)Frames.TB.Den) / 1000;
if (VP.Width <= 0 || VP.Height <= 0) {
Free(true);
snprintf(ErrorMsg, MsgSize, "Codec returned zero size video");
throw ErrorMsg;
}
// sanity check framerate
if (VP.FPSDenominator > VP.FPSNumerator || VP.FPSDenominator <= 0 || VP.FPSNumerator <= 0) {
VP.FPSDenominator = 1;
VP.FPSNumerator = 30;
}
if (InitPP(PP, ErrorMsg, MsgSize)) {
Free(true);
throw ErrorMsg;
}
// Adjust framerate to match the duration of the first frame
if (Frames.size() >= 2) {
unsigned int DTSDiff = (unsigned int)FFMAX(Frames[1].DTS - Frames[0].DTS, 1);
VP.FPSDenominator *= DTSDiff;
}
// Cannot "output" to PPFrame without doing all other initialization
// This is the additional mess required for seekmode=-1 to work in a reasonable way
if (!OutputFrame(DecodeFrame, ErrorMsg, MsgSize)) {
Free(true);
throw ErrorMsg;
}
// Set AR variables
VP.SARNum = CodecContext->sample_aspect_ratio.num;
VP.SARDen = CodecContext->sample_aspect_ratio.den;
}
FFLAVFVideo::~FFLAVFVideo() {
Free(true);
}
int FFLAVFVideo::DecodeNextFrame(int64_t *AStartTime, char *ErrorMsg, unsigned MsgSize) {
AVPacket Packet;
InitNullPacket(&Packet);
int FrameFinished = 0;
*AStartTime = -1;
while (av_read_frame(FormatContext, &Packet) >= 0) {
if (Packet.stream_index == VideoTrack) {
if (*AStartTime < 0)
*AStartTime = Packet.dts;
avcodec_decode_video2(CodecContext, DecodeFrame, &FrameFinished, &Packet);
}
av_free_packet(&Packet);
if (FrameFinished)
goto Done;
}
// Flush the last frames
if (CodecContext->has_b_frames) {
AVPacket NullPacket;
InitNullPacket(&NullPacket);
avcodec_decode_video2(CodecContext, DecodeFrame, &FrameFinished, &NullPacket);
}
if (!FrameFinished)
goto Error;
// Ignore errors for now
Error:
Done:
return 0;
}
FFAVFrame *FFLAVFVideo::GetFrame(int n, char *ErrorMsg, unsigned MsgSize) {
// PPFrame always holds frame LastFrameNum even if no PP is applied
if (LastFrameNum == n)
return OutputFrame(DecodeFrame, ErrorMsg, MsgSize);
bool HasSeeked = false;
int SeekOffset = 0;
int ClosestKF = 0;
if (SeekMode >= 0) {
ClosestKF = Frames.FindClosestVideoKeyFrame(n);
if (SeekMode == 0) {
if (n < CurrentFrame) {
av_seek_frame(FormatContext, VideoTrack, Frames[0].DTS, AVSEEK_FLAG_BACKWARD);
avcodec_flush_buffers(CodecContext);
CurrentFrame = 0;
}
} else {
// 10 frames is used as a margin to prevent excessive seeking since the predicted best keyframe isn't always selected by avformat
if (n < CurrentFrame || ClosestKF > CurrentFrame + 10 || (SeekMode == 3 && n > CurrentFrame + 10)) {
ReSeek:
av_seek_frame(FormatContext, VideoTrack,
(SeekMode == 3) ? Frames[n].DTS : Frames[ClosestKF + SeekOffset].DTS,
AVSEEK_FLAG_BACKWARD);
avcodec_flush_buffers(CodecContext);
HasSeeked = true;
}
}
} else if (n < CurrentFrame) {
snprintf(ErrorMsg, MsgSize, "Non-linear access attempted");
return NULL;
}
do {
int64_t StartTime;
if (DecodeNextFrame(&StartTime, ErrorMsg, MsgSize))
return NULL;
if (HasSeeked) {
HasSeeked = false;
// Is the seek destination time known? Does it belong to a frame?
if (StartTime < 0 || (CurrentFrame = Frames.FrameFromDTS(StartTime)) < 0) {
switch (SeekMode) {
case 1:
// No idea where we are so go back a bit further
if (ClosestKF + SeekOffset == 0) {
snprintf(ErrorMsg, MsgSize, "Frame accurate seeking is not possible in this file\n");
return NULL;
}
SeekOffset -= FFMIN(10, ClosestKF + SeekOffset);
goto ReSeek;
case 2:
case 3:
CurrentFrame = Frames.ClosestFrameFromDTS(StartTime);
break;
default:
snprintf(ErrorMsg, MsgSize, "Failed assertion");
return NULL;
}
}
}
CurrentFrame++;
} while (CurrentFrame <= n);
LastFrameNum = n;
return OutputFrame(DecodeFrame, ErrorMsg, MsgSize);
}