[FFmpeg-user] From mpeg2 to mpeg4

[Lorenzo Travaglio]

Hi all.

I'm a newbie of ffmpeg

My DTv receiver can record on USB key in mpeg2video format. Since the 
size of the record is about 1Gb/hour I want to reduce it to the size 
used by avi movies but I don't be able to perform this transformation.

Here is the output of ffmpeg -i for the file obtained by the recorder:
FFmpeg version SVN-r0.5.1-4:0.5.1-1ubuntu1.2, Copyright (c) 2000-2009 
Fabrice Bellard, et al.
   configuration: --extra-version=4:0.5.1-1ubuntu1.2 --prefix=/usr 
--enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib 
--enable-libgsm --enable-libschroedinger --enable-libspeex 
--enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib 
--disable-stripping --disable-vhook --enable-runtime-cpudetect 
--enable-gpl --enable-postproc --enable-swscale --enable-x11grab 
--enable-libdc1394 --enable-shared --disable-static
   libavutil     49.15. 0 / 49.15. 0
   libavcodec    52.20. 1 / 52.20. 1
   libavformat   52.31. 0 / 52.31. 0
   libavdevice   52. 1. 0 / 52. 1. 0
   libavfilter    0. 4. 0 /  0. 4. 0
   libswscale     0. 7. 1 /  0. 7. 1
   libpostproc   51. 2. 0 / 51. 2. 0
   built on Sep 16 2011 17:04:18, gcc: 4.4.3

Seems stream 0 codec frame rate differs from container frame rate: 50.00 
(50/1) -> 25.00 (25/1)
Input #0, mpeg, from 'prova.mpg':
   Duration: 00:09:03.69, start: 0.180600, bitrate: 5183 kb/s
     Stream #0.0[0x1e0]: Video: mpeg2video, yuv420p, 720x576 [PAR 64:45 
DAR 16:9], 4624 kb/s, 25 tbr, 90k tbn, 50 tbc
     Stream #0.1[0x1c0]: Audio: mp2, 48000 Hz, stereo, s16, 192 kb/s

while this is an output from an avi file:
FFmpeg version SVN-r0.5.1-4:0.5.1-1ubuntu1.2, Copyright (c) 2000-2009 
Fabrice Bellard, et al.
   configuration: --extra-version=4:0.5.1-1ubuntu1.2 --prefix=/usr 
--enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib 
--enable-libgsm --enable-libschroedinger --enable-libspeex 
--enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib 
--disable-stripping --disable-vhook --enable-runtime-cpudetect 
--enable-gpl --enable-postproc --enable-swscale --enable-x11grab 
--enable-libdc1394 --enable-shared --disable-static
   libavutil     49.15. 0 / 49.15. 0
   libavcodec    52.20. 1 / 52.20. 1
   libavformat   52.31. 0 / 52.31. 0
   libavdevice   52. 1. 0 / 52. 1. 0
   libavfilter    0. 4. 0 /  0. 4. 0
   libswscale     0. 7. 1 /  0. 7. 1
   libpostproc   51. 2. 0 / 51. 2. 0
   built on Sep 16 2011 17:04:18, gcc: 4.4.3
Input #0, avi, from '.aMuleAdunanzA/Incoming/Cars - Motori ruggenti.avi':
   Duration: 01:55:19.00, start: 0.000000, bitrate: 845 kb/s
     Stream #0.0: Video: mpeg4, yuv420p, 576x238 [PAR 1:1 DAR 288:119], 
23.98 tbr, 23.98 tbn, 23.98 tbc
     Stream #0.1: Audio: mp3, 44100 Hz, stereo, s16, 112 kb/s

May someone help me?
Many thanks in advance
Lorenzo