[Libav-user] decoding_encoding.c with HEVC

[Peter Steinbach]

Hi to all,

it took me quite some time, but I seem to have achieved encoding a 
synthesized video to an h264 or h265 file and the decode it again. I 
collected bits and pieces from bug trackers, orphaned (unanswered) mails 
to this mailing list and other blog posts to actually made it happen. 
the ffmpeg API documentation didn't help me at all, or I overlooked 
something obvious.

Feel free to help me further, correct me or point me to more intuitive 
documentation either through this mailing list or the github repo which 
contains my code:
https://github.com/psteinb/libav-h26x-sandbox

Best,
Peter

On 08/12/2015 05:10 PM, Peter Steinbach wrote:
> Hi to all,
>
> I've recently started experimenting with ffmpeg to use it in order to
> encode 3D objects (for a scientific purpose rather than stereoscopic
> vision before anyone asks). Based on my missing knowledge in video
> encoding/decoding, I used the ffmpeg example  and modified it
> decoding_encoding.c so that I can create a 3D 8bit object and then
> encode it with HEVC and re-read it back to produce *.pgm files.
>
> However the decoding step produces just 2 images, which is clearly not
> what I was expecting given than I encoded 25 frames. I am also getting
> error messages like
> [hevc @ 0xe58760] Invalid NAL unit 0, skipping.
> During the decoding. Does anyone have an idea what I did wrong?
>
>
> I upload the source code here:
> https://gist.github.com/psteinb/bf12348d799108f390f5
>
> Running ffprobe on the produced *.h265 file yields:
> ffprobe version 2.5.8 Copyright (c) 2007-2015 the FFmpeg developers
>    built on Aug 11 2015 08:55:10 with gcc 4.9.2 (GCC) 20150212 (Red Hat
> 4.9.2-6)
>    configuration: --prefix=/home/steinbac/software/ffmpeg/2.5.8
> --enable-libx265 --enable-libx264 --enable-gpl --enable-shared
>    libavutil      54. 15.100 / 54. 15.100
>    libavcodec     56. 13.100 / 56. 13.100
>    libavformat    56. 15.102 / 56. 15.102
>    libavdevice    56.  3.100 / 56.  3.100
>    libavfilter     5.  2.103 /  5.  2.103
>    libswscale      3.  1.101 /  3.  1.101
>    libswresample   1.  1.100 /  1.  1.100
>    libpostproc    53.  3.100 / 53.  3.100
> Input #0, hevc, from 'ffmpeg_roundtrip.h265':
>    Duration: N/A, bitrate: N/A
>      Stream #0:0: Video: hevc (Main), yuv420p(tv), 352x288, 25 fps, 25
> tbr, 1200k tbn, 25 tbc
>
> Any help would be appreciated!
> Best,
> Peter
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