[FFmpeg-user] From mpeg2 to mpeg4

[Lou]

On Mon, 24 Oct 2011 00:38:50 +0200
Lorenzo Travaglio <lorenzo.travaglio at fastwebnet.it> wrote:

> Il 23/10/2011 21:00, Jonathan Isom ha scritto:
> > ffmpeg -i prova.mpg -vcodec mpeg4 -b 800000 -ac 2 -acodec mp3 -ab
> > 128000 -r 50 -s 720x368 prova2.mpg

Why are you changing the frame rate?

> I compiled latest version of ffmpeg following the instruction in 
> http://ubuntuforums.org/showpost.php?p=9868359&postcount=1289
> 
> It seems work but with the cl you gave the result is the following:
> ffmpeg -i prova.mpg -vcodec mpeg4 -b 800000 -ac 2 -acodec mp3 -ab
> 128000 -r 50 -s 720x368 prova2.mpg
> ffmpeg version N-33990-g42d44ec, Copyright (c) 2000-2011 the FFmpeg 
> developers
>    built on Oct 24 2011 00:22:56 with gcc 4.4.3
>    configuration: --enable-gpl --enable-version3 --enable-nonfree 
> --enable-postproc --enable-libfaac --enable-libopencore-amrnb 
> --enable-libopencore-amrwb --enable-libtheora --enable-libvorbis 
> --enable-libx264 --enable-x11grab
>    libavutil    51. 22. 0 / 51. 22. 0
>    libavcodec   53. 23. 0 / 53. 23. 0
>    libavformat  53. 17. 0 / 53. 17. 0
>    libavdevice  53.  4. 0 / 53.  4. 0
>    libavfilter   2. 44. 1 /  2. 44. 1
>    libswscale    2.  1. 0 /  2.  1. 0
>    libpostproc  51.  2. 0 / 51.  2. 0
> [mp2 @ 0x94c98c0] Header missing
> [mpeg @ 0x94b8a80] max_analyze_duration 5000000 reached at 5016000
> Input #0, mpeg, from 'prova.mpg':
>    Duration: 00:09:03.73, start: 0.132600, bitrate: 5183 kb/s
>      Stream #0:0[0x1e0]: Video: mpeg2video (Main), yuv420p, 720x576
> [SAR 64:45 DAR 16:9], 4624 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc
>      Stream #0:1[0x1c0]: Audio: mp2, 48000 Hz, stereo, s16, 192 kb/s
> Please use -b:a or -b:v, -b is ambiguous

This message is telling you to change -b to -b:v and -ab to -b:a due to
some recent syntax changes.

> Unknown encoder 'mp3'

The MP3 encoder is "libmp3lame". The decoder is called "mp3". You can
see a list of encoders and decoders with: ffmpeg -codecs. Unfortunately,
you skipped the "Install LAME (optional)" section in the compilation
guide, and therefore you do not have libmp3lame support.

> I did remove -acodec mp3 -ab 128000 just to see the result of the
> rest of the process. I obtained a file with a good audio but no
> video :-(
> 
> Good night
> Lorenzo