[FFmpeg-user] From mpeg2 to mpeg4

[Jonathan Isom]

On Sun, Oct 23, 2011 at 1:41 PM, Lorenzo Travaglio
<lorenzo.travaglio at fastwebnet.it> wrote:
> On Sun, 23/10/2011 17:34, Jonathan Isom wrote:
>> Hi
>>    The first thing just about anybody on this list will tell you is
>> that you are using  a
>> very old(2009) version. You should try to install a recent version.
>> FFmpeg is under
>> constant development so many options have changed and codecs improved.
>>   It would
>> also be beneficial to know the command line you tried. Also are you
>> wanting just
>> mpeg4 or mpeg4 AVC(aka h.264)?
>
> Thank you Jonathan for your answer.
> This package is declared as "up-to-date" by apt-get. However I will try to
> download the source and to recompile even because some switches like '-a' to
> change the aspect ratio do not work.
>
> I tried many command line like "ffmpeg -i prova.mpg -vcodec mpeg4
> prova4.mpg" but the results are very poor. In this particular case I
> obtained a reduced but not visible file. In other cases I obtained reduced
> versions but video was very poor, as with "ffmpeg -i prova.mpg -s 720*368
> prova3.mpg" or "ffmpeg -i prova.mpg -r 50 prova2.mpg".

You may wish to add a bitrate for the video(-b) and audio(-ab). -r is
for framerate. you may get better results
with 25 than 50 though that cuts it in half.  You'll have to test for
your needs.

ffmpeg -i prova.mpg -vcodec mpeg4 -b 800000 -ac 2 -acodec mp3 -ab
128000 -r 50 -s 720x368 prova2.mpg

> The file "prova.mpg" is the result of a cut made on the record of one tv
> program to remove commercials and other not interesting parts. The cut has
> been made by mpgtx.
>
> Before reply to your question I admit to ignore the difference between the
> two formats you ask. I would try with this small video and to check if the
> tv decoder is able to read the format. Not all formats are read by my DTV
> decoder.

Seeing as you are using a DTV decoder you probably want standard mpeg4.


HTH

Jonathan


> Here I enclose the output of the -vcodec mpeg4 command line. I don't know if
> the errors reported are important or not.
>
> Thank you
> Lorenzo
>
> ----
> 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
> Output #0, mpeg, to 'prova4.mpg':
>    Stream #0.0: Video: mpeg4, yuv420p, 720x576 [PAR 64:45 DAR 16:9], q=2-31,
> 200 kb/s, 90k tbn, 25 tbc
>    Stream #0.1: Audio: mp2, 48000 Hz, stereo, s16, 64 kb/s
> Stream mapping:
>  Stream #0.0 -> #0.0
>  Stream #0.1 -> #0.1
> Press [q] to stop encoding
> [mpeg2video @ 0x8ec3b90]00 motion_type at 16 1e=69.05 bitrate= 470.5kbits/s
> [mpeg2video @ 0x8ec3b90]00 motion_type at 8 2
> [mpeg2video @ 0x8ec3b90]ac-tex damaged at 2 3
> [mpeg2video @ 0x8ec3b90]00 motion_type at 5 4
> [mpeg2video @ 0x8ec3b90]ac-tex damaged at 5 5
> [mpeg2video @ 0x8ec3b90]invalid mb type in B Frame at 10 6
> [mpeg2video @ 0x8ec3b90]00 motion_type at 1 7
> [mpeg2video @ 0x8ec3b90]00 motion_type at 2 8
> [mpeg2video @ 0x8ec3b90]invalid cbp at 26 9
> [mpeg2video @ 0x8ec3b90]00 motion_type at 10 10
> [mpeg2video @ 0x8ec3b90]00 motion_type at 34 11
> [mpeg2video @ 0x8ec3b90]00 motion_type at 1 12
> [mpeg2video @ 0x8ec3b90]00 motion_type at 2 13
> [mpeg2video @ 0x8ec3b90]00 motion_type at 1 14
> [mpeg2video @ 0x8ec3b90]00 motion_type at 11 15
> [mpeg2video @ 0x8ec3b90]invalid mb type in B Frame at 1 16
> [mpeg2video @ 0x8ec3b90]mb incr damaged
> [mpeg2video @ 0x8ec3b90]00 motion_type at 7 18
> [mpeg2video @ 0x8ec3b90]00 motion_type at 43 19
> [mpeg2video @ 0x8ec3b90]00 motion_type at 14 20
> [mpeg2video @ 0x8ec3b90]00 motion_type at 6 21
> [mpeg2video @ 0x8ec3b90]00 motion_type at 11 22
> [mpeg2video @ 0x8ec3b90]00 motion_type at 1 23
> [mpeg2video @ 0x8ec3b90]00 motion_type at 3 24
> [mpeg2video @ 0x8ec3b90]00 motion_type at 3 26
> [mpeg2video @ 0x8ec3b90]00 motion_type at 1 27
> [mpeg2video @ 0x8ec3b90]00 motion_type at 3 28
> [mpeg2video @ 0x8ec3b90]00 motion_type at 13 29
> [mpeg2video @ 0x8ec3b90]00 motion_type at 1 30
> [mpeg2video @ 0x8ec3b90]00 motion_type at 4 31
> [mpeg2video @ 0x8ec3b90]00 motion_type at 8 32
> [mpeg2video @ 0x8ec3b90]00 motion_type at 4 34
> [mpeg2video @ 0x8ec3b90]00 motion_type at 1 35
> [mpeg2video @ 0x8ec3b90]Warning MVs not available
> [mpeg2video @ 0x8ec3b90]concealing 1575 DC, 1575 AC, 1575 MV errors
> frame=13590 fps=116 q=31.0 Lsize=   31120kB time=543.36 bitrate=
> 469.2kbits/s
> video:26616kB audio:4245kB global headers:0kB muxing overhead 0.838791%
> ----
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