[FFmpeg-user] Setting 'crf' option when converting with ffmpeg

[Henk D. Schoneveld]

On 17 Dec 2013, at 07:51, Andrei Petru Mura <mapandrei at gmail.com> wrote:

> I have a H264 encoded file that I try to convert to a mjpeg format.
> That's the command that I issue and its output:
> 
> */home/netnfork/bin/ffmpeg -i ./Event20131026000020003.avi -crf 12 -c:v
> mjpeg -vf hflip ./out.avi*
> *ffmpeg version git-2013-10-15-c35d29a Copyright (c) 2000-2013 the FFmpeg
> developers*
> *  built on Oct 15 2013 11:56:38 with gcc 4.4.7 (GCC) 20120313 (Red Hat
> 4.4.7-3)*
> *  configuration: --prefix=/home/netnfork/ffmpeg_build
> --extra-cflags=-I/home/netnfork/ffmpeg_build/include
> --extra-ldflags=-L/home/netnfork/ffmpeg_build/lib
> --bindir=/home/netnfork/bin --extra-libs=-ldl --enable-gpl --enable-nonfree
> --enable-libfdk_aac --enable-libmp3lame --enable-libopus --enable-libvorbis
> --enable-libvpx --enable-libx264 --enable-libfreetype --enable-libspeex
> --enable-libtheora*
>  libavutil      52. 46.101 / 52. 46.101
>  libavcodec     55. 36.100 / 55. 36.100
>  libavformat    55. 19.102 / 55. 19.102
>  libavdevice    55.  4.100 / 55.  4.100
>  libavfilter     3. 88.101 /  3. 88.101
>  libswscale      2.  5.101 /  2.  5.101
>  libswresample   0. 17.103 /  0. 17.103
>  libpostproc    52.  3.100 / 52.  3.100
> [avi @ 0xb710e20] probed stream 1 failed
> [avi @ 0xb710e20] Stream #2: not enough frames to estimate rate; consider
> increasing probesize
> [avi @ 0xb710e20] Could not find codec parameters for stream 1 (Subtitle:
> none): unknown codec
> Consider increasing the value for the 'analyzeduration' and 'probesize'
> options
> [avi @ 0xb710e20] Could not find codec parameters for stream 2 (Subtitle:
> none): unknown codec
> Consider increasing the value for the 'analyzeduration' and 'probesize'
> options
> *Input #0, avi, from './Event20131026000020003.avi':*
> *  Duration: 00:00:43.67, start: 0.000000, bitrate: 8034 kb/s*
> *    Stream #0:0: Video: h264 (High) (X264 / 0x34363258), yuvj420p(pc),
> 1920x1080, 30 fps, 30 tbr, 30 tbn, 30 tbc*
> *    Stream #0:1: Subtitle: none*
> *    Stream #0:2: Subtitle: none*
> *Codec AVOption crf (Select the quality for constant quality mode)
> specified for output file #0 (./out.avi) has not been used for any stream.
> The most likely reason is either wrong type (e.g. a video option with no
> video streams) or that it is a private option of some encoder which was not
> actually used for any stream.*
> *File './out.avi' already exists. Overwrite ?* [y/N] y
> Output #0, avi, to './out.avi':
>  Metadata:
>    ISFT            : Lavf55.19.102
>    Stream #0:0: Video: mjpeg (MJPG / 0x47504A4D), yuvj420p, 1920x1080,
> q=2-31, 200 kb/s, 30 tbn, 30 tbc
> Stream mapping:
>  Stream #0:0 -> #0:0 (h264 -> mjpeg)
> Press [q] to stop, [?] for help
> frame=  260 fps=110 q=0.0 Lsize=   24737kB time=00:00:08.66
> bitrate=23382.6kbits/s
> video:24726kB audio:0kB subtit ...
> 
> The red written text is the problem that I don't know how to deal with. Can
> anybody tell me how to deal with this problem? I want to specify the "crf"
> for this conversion because the quality resulted is very bad in a few
> specific files. Why does "crf" does not take effect when I specify it in my
> scenario?
crf is an option when using c:v libx264 NOT with c:v mjpeg
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