[FFmpeg-user] Problems to rescale video for a specific hardware (Beaglebone)

[meino.cramer at gmx.de]

Hi,

(using a recent Gentoo Linux on a AMD64 system)

the second half of this sunday I have spent searching
the net and testing what I have found ... unfortunately
without success.

I have a piece of video recorded from a DVB-T receiver.

ffprobe shows this information about the file:
ffprobe version 0.10.3 Copyright (c) 2007-2012 the FFmpeg developers
  built on Jun 17 2012 20:02:03 with gcc 4.5.3
  configuration: --prefix=/usr --libdir=/usr/lib64 --shlibdir=/usr/lib64 --mandir=/usr/share/man --enable-shared --cc=x86_64-pc-linux-gnu-gcc --cxx=x86_64-pc-linux-gnu-g++ --ar=x86_64-pc-linux-gnu-ar --optflags='-march=native -O2 -pipe -msse3' --extra-cflags='-march=native -O2 -pipe -msse3' --extra-cxxflags='-march=native -O2 -pipe -msse3' --disable-static --enable-gpl --enable-postproc --enable-avfilter --disable-stripping --disable-debug --disable-doc --disable-network --disable-vaapi --enable-libmp3lame --enable-libvorbis --disable-indev=v4l --disable-indev=oss --enable-x11grab --disable-outdev=oss --enable-libopenjpeg --disable-amd3dnow --disable-amd3dnowext --disable-altivec --disable-avx --disable-mmx2 --disable-ssse3 --disable-vis --disable-neon --cpu=host --enable-hardcoded-tables
  libavutil      51. 35.100 / 51. 35.100
  libavcodec     53. 61.100 / 53. 61.100
  libavformat    53. 32.100 / 53. 32.100
  libavdevice    53.  4.100 / 53.  4.100
  libavfilter     2. 61.100 /  2. 61.100
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0.  6.100 /  0.  6.100
  libpostproc    52.  0.100 / 52.  0.100
[mpeg @ 0x19693e0] max_analyze_duration 5000000 reached at 5000000
Input #0, mpeg, from 'Record.mpg':
  Duration: 02:28:56.72, start: 0.264656, bitrate: 3159 kb/s
    Stream #0:0[0x1e0]: Video: mpeg2video (Main), yuv420p, 720x576 [SAR 64:45 DAR 16:9], 2072 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc
    Stream #0:1[0x1c0]: Audio: mp2, 48000 Hz, stereo, s16, 192 kb/s

My desktop PC is able to play this video without any problems.

But I want also check, whether my Beaglebone (OMAP35x) single board
computer is capable of playing the video.

The display has 800x480 pixel with 16 bit colordepth.

With only a little stuttering using 

    mplayer -vo x11 Video.mpg

it is possible to play the video. 

But: The video does not fit onto the screen and has the wrong aspect
ration... "egghead syndrome"...

(I currently have no ffmpeg combo on the Beaglebone available since it
does not compile natively on it due to too less memory).

There is currently no hardware acceleration available on the board.

My plan is to resize the video to have 16:9 aspect ration (no
anamorphic...that is the pixel are quare sized with equal x and y
length) and downscaled to fit the screen size. The process should
neither create a  video in much lower quality nor should the file
soze explode.

I tried things like

ffmpeg -vf scale=-1:480 -i <input> <output>
ffmpeg -vf scale=-1:480 -qscale <n> -i <input> <output>   with <n>=1...4
I also tried to use "-setdar 16:9" which is documented on the net but not 
accepted by my ffmpeg.

Regardless what I am doing the resulting video is blown in size and/or has
crippled quality but it is always suffering from the egghead
syndrome when played on the beaglebone.

What I am doing so badly wrong here and why does all the stuff from
the net not work for me ?

Any help is very appreciated! Thank you very much in advance!

Best regards,
mcc