[Libav-user] Disappearing / missing frames from h264 source

Daan Heemskerk daan.heemskerk at gmail.com
Tue Dec 24 02:32:04 EET 2019


I have a problem that has been driving me crazy for a day.

At this moment I can't post source code; for that I have to write a 
small test program tomorrow,

The problem:


I receive packages from a h268 webcam using:

if( av_read_frame(this->pFormatContextIn, pPacket) < 0 ) break;

Normally those packages have an increasing dts and pts with an increment 
of 3600.

Timebase is 1/ 90000 fps is 25 -> So this is perfect.

But at some moments this starts to flip up to the point where the dts 
and pts have an increment of 90000 ( one second ).

I repeatedly call the openH264 decoder but only get one frame.

If I look at the video I encode the time is correct; the movie stalls, 
skips some frames and continues.
( I use the input pts and that means the input pts is correct. )

The problem is where did the frames go ...



Both AVCONV and VLC MEDIA PLAYER play the same stream with almost no 

I tried both:


and the new:


and I have read the source code of avconv.c

If I just copy the packages I also have a correct video stream.

So I miss something at the moment I get the frames using:

avcodec_receive_frame ( repeated )

I don't even mangle with the pts and dts ... I have a movie of a clock; 
the pts I receive seems perfect.

The dial sometimes just stops for a while and then jumps over the gap.

Does someone know if there is some setting or some small thing that 
would make my frames disappear?

Thank you,


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