[mythtv-users] Looking for trancoding suggestions

[James Pifer]

I have a new device that's going to serve a dual purpose. I bought a
Galaxy TVisto. It's a USB/Firewire 3.5 HD enclosure/Media Player. I plan
on using it to backup my videos and to take on trips. I've tested it
using a power inverter in our van and it works. 

My videos are currently all stored as MPEG2 files. I'd like to transcode
the videos so I can store them as smaller files, but obviously I'd like
them to still look good. Another caveat is that I need them to be either
MPEG1 or MPEG2 because I also use a MediaMVP. 

Can anyone suggest what settings they use for transcoding? So far I've
been using ffmpeg and mencoder. I'm not partial to either one. I've
transcoded some using a 3K and 2.5K bitrates. Quality at 3K is
acceptable, but it only shrinks a 1.5GB video to 1GB. I was hoping to
cut it closer to half.

When I run ffmpeg I get this for the video input:
Input #0, mpeg, from 'Monster_Beasts.mpg':
  Duration: 00:43:29.5, start: 0.244756, bitrate: 5004 kb/s
  Stream #0.0[0x1e0]: Video: mpeg2video, yuv420p, 704x480, 6000 kb/s, 29.97 fps(r)
  Stream #0.1[0x1c0]: Audio: mp2, 48000 Hz, stereo, 384 kb/s

Plus, it doesn't matter whether I encode to MPEG1 or MPEG2 the quality
seems the same. Should I see a difference? Here's a couple examples I've
used: 

ffmpeg -i Monster_Beasts.mpg -vcodec mpeg2video -b 3000000 -ab 192 -y Monster_Beasts_3K-bitrate_ffmpeg_mpeg1.mpg

mencoder Monster_Beasts.mpg -ovc frameno -o frameno.avi -oac mp3lame -lameopts vbr=3
mencoder Monster_Beasts.mpg -of mpeg -mpegopts format=dvd:vaspect=4/3:vframerate=30 -srate 48000 -ofps 30000/1001 -ovc lavc -oac lavc -lavcopts vcodec=mpeg2video:vrc_buf_size=1835:keyint=18:vrc_maxrate=9800:vbitrate=3000:aspect=4/3:acodec=ac3:abitrate=192:vpass=1 -oac copy -o Monster_Beasts_3K-bitrate_mencoder.mpg
mencoder Monster_Beasts.mpg -of mpeg -mpegopts format=dvd:vaspect=4/3:vframerate=30  -srate 48000 -ofps 30000/1001 -ovc lavc -oac lavc -lavcopts vcodec=mpeg2video:vrc_buf_size=1835:keyint=18:vrc_maxrate=9800:vbitrate=3000:aspect=4/3:acodec=ac3:abitrate=192:vpass=2 -oac copy -o Monster_Beasts_3K-bitrate_mencoder.mpg

Any help is appreciated. I've done tons of searching (googling) and lots
of trial and error. Just looking for anyone that has known good
solutions. 

Thanks,
James