[Libav-user] Access to motions vectors and macroblock in P_FRAME lib264

NDJORE BORIS ndjoreboris at gmail.com
Wed Mar 6 17:07:42 EET 2019

Le mer. 6 mars 2019 à 14:19, Carl Eugen Hoyos <ceffmpeg at gmail.com> a écrit :

> 2019-03-06 11:56 GMT+01:00, NDJORE BORIS <ndjoreboris at gmail.com>:
> > I want to extract all motion vectors in P_type mocroblock  in a
> > P_frame during encoding h264 video with libx264 (x264).
> Since x264 != FFmpeg, this cannot be answered here.
> (I don't know if x264 offers an api to export the info but
> if the api exists, it is not supported by FFmpeg).
> -------------------------------------------------------------------------------------------------
> Ok. It means that it is not possible to have such info with x264
> (x264Context)?

  I understand and I want to know if the only encoder we can use to
transcode h264
video format is x264? Try to enlight me, please.
I ask this question because when I try to transcode h264 video fromat with
it encoder
[ avcodec_find_encoder(dec_ctx->codec_id)  ], I have the error:
"[h264_vaapi @ 0x1b011c0] A hardware frames reference is required to
associate the encoding device.
Cannot open video encoder for stream #0 "

When I use MPEG4 (AV_CODEC_ID_MPEG4), The transcoding is ok but there are
some error in P_frame:

mpeg4 @ 0x191ec00] P cbpy damaged at 28 0
[mpeg4 @ 0x191ec00] Error at MB: 28
[mpeg4 @ 0x191ec00] concealing 920 DC, 920 AC, 920 MV errors in P frame

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