[Libav-user] avcodec_encode_video2() crashes after encoding a few pictures

[Alex Cohn]

On Jun 27, 2013 10:51 PM, "Paul B Mahol" <onemda at gmail.com> wrote:
>
> On 6/27/13, Arvind Raman <arvind_raman at yahoo.com> wrote:
> > I am developing an application using the FFmpeg libraries and am facing
a
> > crash issue that I am finding extremely hard to debug. My printf logs
> > suggest that crash happens within the avcodec_encode_video2() function
but I
> > am not sure what is causing the crash.
> >
> > Just for debugging purpose, I created the following infinite loop on the
> > "encode" thread. The loop iterates several times and crashes somewhere
in
> > between the 350th and the 400th iteration. The crash is not
deterministic.
> > Please note there are video decode (libavcodec) and demux (libavformat)
> > threads running in parallel that are interrupting the
> > avcodec_encode_video2() function. Could this be a problem.
> >
> > Do you spot anything that might be causing the crash? I am using the
x.264
> > encoder. The only error log that I get on the terminal is "Segmentation
> > fault (core dumped)" so I am finding it hard to proceed. Is there
anyway to
> > get x.264 to print where the crash might be happening.
> >
> > Its quite likely that this might be a silly coding mistake from my end,
but
> > just wanted to get a quick check done from you all and receive your
> > suggestions.
> >
> > while(1)
> > {
> >     av_init_packet(&encode_packet);
> >     frame->pts += 3750;
> >
> >     frame->data[0] = frame_buf;
> >     frame->data[1] = frame->data[0] + (frame->linesize[0] *
> > encoder_ctx->height);
> >     frame->data[2] = frame->data[1] + (frame->linesize[1] *
> > (encoder_ctx->height / 2));
>
> This looks wrong, use memcpy instead.
>
> >     encode_status = avcodec_encode_video2(encoder_ctx, &encode_packet,
> > frame, &got_packet);
> >
> >     av_free_packet(&encode_packet);
> > }
> >
> > I tried running valgrind as well but that didn't throw any illegal
memory
> > access and it throws the following error. Could this be causing the
crash?
> > What is this error about? I saw similar error messages elsewhere as
well,
> > but don't think I found any solution there.
> >
> >
> > vex amd64->IR: unhandled instruction bytes: 0x66 0xF 0x38 0x41 0xC0
0x66 0xF
> > 0x7E
> > ==10933== valgrind: Unrecognised instruction at address 0x51393bc.
> > ==10933==    at 0x51393BC: ??? (in /usr/local/lib/libx264.so.133)
> > ==10933==    by 0x2000200020001F: ???
> > ==10933== Your program just tried to execute an instruction that
Valgrind
> > ==10933== did not recognise.  There are two possible reasons for this.
> > ==10933== 1. Your program has a bug and erroneously jumped to a non-code
> > ==10933==    location.  If you are running Memcheck and you just saw a
> > ==10933==    warning about a bad jump, it's probably your program's
fault.
> > ==10933== 2. The instruction is legitimate but Valgrind doesn't handle
it,
> > ==10933==    i.e. it's Valgrind's fault.  If you think this is the case
or
> > ==10933==    you are not sure, please let us know and we'll try to fix
it.
> > ==10933== Either way, Valgrind will now raise a SIGILL signal which will
> > ==10933== probably kill your program.
> > ==10933==
> > ==10933== Process terminating with default action of signal 4 (SIGILL)
> > ==10933==  Illegal opcode at address 0x51393BC
> > ==10933==    at 0x51393BC: ??? (in /usr/local/lib/libx264.so.133)
> > ==10933==    by 0x2000200020001F: ???
> >
> > Any help would be greatly appreciated!!!
> >
> > Best regards
> > Arvind

Or even easier, there exists avpicture_fill((AVPicture *) frame, frame_buf,
encoder_ctx->pix_fmt, frame->width, frame->height);

BR,
Alex Cohn
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://ffmpeg.org/pipermail/libav-user/attachments/20130628/1f6fa328/attachment.html>