[mythtv-users] Looking for trancoding suggestions

[Brian Wood]

James Pifer wrote:
> 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. 

The best solution I can think of is to just put a bigger hard drive in
the enclosure. 500GB drives are under $150 these days, and how much
video do you really need to store? That's close to 250 hours at full DVD
rate for SD.

It's the old "time vs. money" equation I suppose.

BEWW