CODEWITHSUNDEEP
ffmpeglibav
Hudson Cavazin
Hudson Cavazin

Reputation: 413

FFmpeg api, how to mux raw h264 without pts timestamps to mp4 or m3u8

I tried to follow the following example: https://github.com/FFmpeg/FFmpeg/blob/master/doc/examples/muxing.c

Problem: my stream h264 is not possible to do demux, so the frames I send to the encoder have some blank data, example pkt.pts == AV_NOPTS_VALUE, this causes an error when calling the av_interleaved_write_frame (mux) function.

Considering that the framerate is not constant, how do I generate the pkt.pts correctly from the video frames as I get it from the raw live stream?

Is there any way for ffmpeg libav to automatically calculate pkt.pts, pkt.dts timestamps as I send frames to the muxer with av_interleaved_write_frame?

Upvotes: 1

Views: 810

Answers (1)

PookyFan
PookyFan

Reputation: 840

Quite an old question, but it's still worth answering, since FFMPEG doesn't make it easy.

Consequent frames' PTS and DTS (in generic case they would be the same) shall be equal to previousPacketPTS + curtrentPacket.duration. Your curtrentPacket.duration is just what it sounds - information of how long given frame would be displayed before switching to the next one. Remember that this duration is in stream's time base units, which is rational of a second (for example 1/50 time base means the shortest frame of that stream can last 1/50 sec, or 20 ms). So you can translate time difference between two video frames into video frame duration, ie. when you receive a video frame, then it's duration would be the time needed for the next frame to come - again, in stream's time base. And that's all you need for calculating PTS and DTS for the frames.

Upvotes: 0

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