plan for converting SageTV mpg's to smaller files.

[Verlager]

I have 400 20-minute files of Rachel Ray's 30-minute meals, each mpg file averages 800 mb. I'd like to CLI batch reduce the filesize to <400 mb and the screen size down from 720x480. I am a Linux Mint user so I have ffmpeg, mencoder and transcode, all of which I have used semi-sucessfully. I think x264 would be the best format.

I will simply access these files from the HD, no need for any format to burn to CD/DVD.

I tried a shell script to convert to flv:

for i in *.mpg; do
prefix=${i%.*}; suffix=${i#*.}; target=$prefix".flv"
ffmpeg -y  -i "$i" -threads 2 -s 320x240   -r 29.97 -threads 1 -pix_fmt yuv420p  -g 300  -qmin 3  -b 512k -async 50  -acodec mp3  -ar 44100 -ac 2 -ab 128k "$target"
done

But the audio was often out of sync with the video. What would be a reliable, reasonable fast, reasonably high quality (no pixelization) method? I'm open to suggestions!

[GMaq]

Hi,
Use WinFF, the H.264 *iPod Linux* presets should be perfect. Don't let the iPod name fool you they are optimized for TV Out use. I use them all the time on my HTPC.
For best results since you are a Linux Mint user I would recommend the latest Medibuntu ffmpeg, or even better the "stable" ffmpeg at www.debian-multimedia.org.

[Verlager]

Thank you very much! WinFF is an excellent front end for ffmpeg. On my P4 3.0 gHz, it took nearly 40 mins. to process a 90 mb file with the H264 *.ipod Linux* (4:3) setting, but the results were spectacular. Original .mpg file size = 888 mb, Processed to .mp4 file size = 172 mb, with no discernable loss in video or audio quality. A reduction factor of 7. Impressive!

I guess I will temporarily dedicate a computer to processing these 400 files, probably take about 11 days to convert. Unless somebody has a faster solution.

[GMaq]

Hi Again,
I have faster presets up on the WinFF forum in the "Presets" section, they work better for 2-pass, but you could try them and see what you think. Better Quality = Slower Encoding no matter what encoder you use.

[Verlager]

I can't find the WinFF forum Presets section. Could somebody please tell me where it is?

[GMaq]

Sorry,
I should have linked it before, I was short on time. here's the link to the preset i was referring to:

http://biggmatt.com/winff-forums/index.php?topic=54.0

[Verlager]

OK, that will work fine for my not-so-valuable Rachel Ray 30-minute meals mpg collection. I will probably watch each one, evaluate it, and throw away 75% of them.

I have a DVD collection, and I routinely convert all the .vob files on each DVD to a single .mpg file in Windows XP with the womble video editor. I'm kind of new to Linux video editing. I have used avidemux and WinFF. I will be getting a new computer soon, so processing time will probably not be a factor.

I want each of these ~4GB mpg files to be reduced down to 1 GB. -while retaining most of the quality. (It's not like they are junk media clips.) I will process them in Linux with WinFF. Based on your advice, I have used WinFF with the output setting of H264 *iPod Linux*, and am happy with the result.

Is this also a good format for converting large DVD quality widescreen 16:9 mpg files? Note that they will simply be stored on a server and only viewed on a computer screen, never on a TV, never burned to a CD/DVD. I like to keep an open mind and not be locked in to a single format.

I see I have a lot of options as to choosing a format. What format will give me 4:1 or better compression and still retain much of the quality of the original mpg file?

The other formats I see are:

NTCS good/high quality (16:9 / anamorphic),
xViD in AVI (16:9 / anamorphic)
xViD for iPod (16:9)

What's your take on output selection format as to low / med / high quality?

[GMaq]

Hello Again,

Well to be honest I WAS trying to be locked into a format (.mp4 for iPod) but after I had done some presets for WinFF I discovered that Higher Resolution H.264 iPod files were also good enough for general use and I started backing up my DVD collection directly to the iPod presets and watching them on my HTPC. Even sitting 8 feet away from a 44" Plasma they look very good and close enough to the DVD source not to detract from enjoying them. As an added bonus they are still iPod compliant for portable use and the kids to take them on the go.

As for future formats Who Really Knows? H.264 is definitely the best quality for filesize option right now and will give you better than 4:1 compression. I would stay away from XviD it's heyday for viewing on a computer is over and takes far more bitrate ( and thus larger file size) for equivalent quality to H.264. I would suggest trying converting a clip with the *iPod Linux* and H.264 High Quality presets and let your eyes be the judge. The Anamorphic presets are for Widescreen movies with a 2.35-2.40 aspect ratio, those presets automatically crop off the black bars and adjust the aspect ratio for the converted file. The Anamorphic presets are the same "quality" as the Widescreen and Fullscreen presets. If you are not sure the (16:9) presets will work as is for both regular and anamorphic widescreen DVDs.

So in summary (re WinFF presets)

Medium to Low Quality -> Xvid for iPod/ XviD in AVI
Very Good Quality -> *iPod Linux* Fast 2-Pass or *iPod Linux* 1-Pass
Best Quality (but slower conversion) -> H.264 High Quality