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Switch to pkt.duration for incrementing PTS, and rename the 2 timesta…
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…mp variables to something more sane.
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@jonoomph
jonoomph committed Jun 26, 2021
1 parent 5b524ab commit 850140d
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Showing 2 changed files with 22 additions and 23 deletions.
41 changes: 20 additions & 21 deletions src/FFmpegWriter.cpp
View file
Expand Up @@ -84,7 +84,7 @@ FFmpegWriter::FFmpegWriter(const std::string& path) :
path(path), fmt(NULL), oc(NULL), audio_st(NULL), video_st(NULL), samples(NULL),
audio_outbuf(NULL), audio_outbuf_size(0), audio_input_frame_size(0), audio_input_position(0),
initial_audio_input_frame_size(0), img_convert_ctx(NULL), cache_size(8), num_of_rescalers(32),
rescaler_position(0), video_codec_ctx(NULL), audio_codec_ctx(NULL), is_writing(false), write_video_count(0), write_audio_count(0),
rescaler_position(0), video_codec_ctx(NULL), audio_codec_ctx(NULL), is_writing(false), video_timestamp(0), audio_timestamp(0),
original_sample_rate(0), original_channels(0), avr(NULL), avr_planar(NULL), is_open(false), prepare_streams(false),
write_header(false), write_trailer(false), audio_encoder_buffer_size(0), audio_encoder_buffer(NULL) {

Expand Down Expand Up @@ -847,7 +847,7 @@ void FFmpegWriter::flush_encoders() {
for (;;) {

// Increment PTS (in frames and scaled to the codec's timebase)
write_video_count += av_rescale_q(1, av_make_q(info.fps.den, info.fps.num), video_codec_ctx->time_base);
video_timestamp += av_rescale_q(1, av_make_q(info.fps.den, info.fps.num), video_codec_ctx->time_base);

AVPacket pkt;
av_init_packet(&pkt);
Expand Down Expand Up @@ -906,7 +906,7 @@ void FFmpegWriter::flush_encoders() {
av_init_packet(&pkt);
pkt.data = NULL;
pkt.size = 0;
pkt.pts = pkt.dts = write_audio_count;
pkt.pts = pkt.dts = audio_timestamp;

/* encode the image */
int error_code = 0;
Expand All @@ -927,7 +927,7 @@ void FFmpegWriter::flush_encoders() {

// Since the PTS can change during encoding, set the value again. This seems like a huge hack,
// but it fixes lots of PTS related issues when I do this.
pkt.pts = pkt.dts = write_audio_count;
pkt.pts = pkt.dts = audio_timestamp;

// Scale the PTS to the audio stream timebase (which is sometimes different than the codec's timebase)
av_packet_rescale_ts(&pkt, audio_codec_ctx->time_base, audio_st->time_base);
Expand All @@ -944,13 +944,12 @@ void FFmpegWriter::flush_encoders() {
"error_code", error_code);
}

// deallocate memory for packet
// Increment PTS by duration of packet
audio_timestamp += pkt.duration;

// deallocate memory for packet
AV_FREE_PACKET(&pkt);
}

// Increment PTS (in samples and scaled to the codec's timebase)
// for some reason, it requires me to multiply channels X 2
write_audio_count += av_rescale_q(audio_input_position / (audio_codec_ctx->channels * av_get_bytes_per_sample(AV_SAMPLE_FMT_S16)), av_make_q(1, info.sample_rate), audio_codec_ctx->time_base);
}

}
Expand Down Expand Up @@ -1015,8 +1014,8 @@ void FFmpegWriter::Close() {
}

// Reset frame counters
write_video_count = 0;
write_audio_count = 0;
video_timestamp = 0;
audio_timestamp = 0;

// Free the context which frees the streams too
avformat_free_context(oc);
Expand Down Expand Up @@ -1818,7 +1817,7 @@ void FFmpegWriter::write_audio_packets(bool is_final) {
}

// Set the AVFrame's PTS
frame_final->pts = write_audio_count;
frame_final->pts = audio_timestamp;

// Init the packet
AVPacket pkt;
Expand All @@ -1827,7 +1826,7 @@ void FFmpegWriter::write_audio_packets(bool is_final) {
pkt.size = audio_encoder_buffer_size;

// Set the packet's PTS prior to encoding
pkt.pts = pkt.dts = write_audio_count;
pkt.pts = pkt.dts = audio_timestamp;

/* encode the audio samples */
int got_packet_ptr = 0;
Expand Down Expand Up @@ -1869,7 +1868,7 @@ void FFmpegWriter::write_audio_packets(bool is_final) {

// Since the PTS can change during encoding, set the value again. This seems like a huge hack,
// but it fixes lots of PTS related issues when I do this.
pkt.pts = pkt.dts = write_audio_count;
pkt.pts = pkt.dts = audio_timestamp;

// Scale the PTS to the audio stream timebase (which is sometimes different than the codec's timebase)
av_packet_rescale_ts(&pkt, audio_codec_ctx->time_base, audio_st->time_base);
Expand All @@ -1886,8 +1885,8 @@ void FFmpegWriter::write_audio_packets(bool is_final) {
ZmqLogger::Instance()->AppendDebugMethod("FFmpegWriter::write_audio_packets ERROR [" + (std::string) av_err2str(error_code) + "]", "error_code", error_code);
}

// Increment PTS
write_audio_count += FFMIN(audio_input_frame_size, audio_input_position);
// Increment PTS by duration of packet
audio_timestamp += pkt.duration;

// deallocate AVFrame
av_freep(&(frame_final->data[0]));
Expand Down Expand Up @@ -2028,7 +2027,7 @@ bool FFmpegWriter::write_video_packet(std::shared_ptr<Frame> frame, AVFrame *fra
pkt.size = sizeof(AVPicture);

// Set PTS (in frames and scaled to the codec's timebase)
pkt.pts = write_video_count;
pkt.pts = video_timestamp;

/* write the compressed frame in the media file */
int error_code = av_interleaved_write_frame(oc, &pkt);
Expand All @@ -2050,7 +2049,7 @@ bool FFmpegWriter::write_video_packet(std::shared_ptr<Frame> frame, AVFrame *fra
pkt.pts = pkt.dts = AV_NOPTS_VALUE;

// Assign the initial AVFrame PTS from the frame counter
frame_final->pts = write_video_count;
frame_final->pts = video_timestamp;
#if USE_HW_ACCEL
if (hw_en_on && hw_en_supported) {
if (!(hw_frame = av_frame_alloc())) {
Expand Down Expand Up @@ -2135,6 +2134,9 @@ bool FFmpegWriter::write_video_packet(std::shared_ptr<Frame> frame, AVFrame *fra
}
}

// Increment PTS (in frames and scaled to the codec's timebase)
video_timestamp += pkt.duration;

// Deallocate packet
AV_FREE_PACKET(&pkt);
#if USE_HW_ACCEL
Expand All @@ -2147,9 +2149,6 @@ bool FFmpegWriter::write_video_packet(std::shared_ptr<Frame> frame, AVFrame *fra
#endif // USE_HW_ACCEL
}

// Increment PTS (in frames and scaled to the codec's timebase)
write_video_count += av_rescale_q(1, av_make_q(info.fps.den, info.fps.num), video_codec_ctx->time_base);

// Success
return true;
}
Expand Down
4 changes: 2 additions & 2 deletions src/FFmpegWriter.h
View file
Expand Up @@ -151,8 +151,8 @@ namespace openshot {
int cache_size;
bool is_writing;
bool is_open;
int64_t write_video_count;
int64_t write_audio_count;
int64_t video_timestamp;
int64_t audio_timestamp;

bool prepare_streams;
bool write_header;
Expand Down

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