Which settings are best for NTSC TV recording (encoding to XviD)?

[xtknight]

OK...a couple questions here. What exactly do matrices help with? Better image quality per megabyte basically? Also, what's the best matrix to use for encoding high-bit rate MPEG2 recorded ntsc analog tv shows into small MPEG-4/XviD files? also what is the difference between an inter/intra matrix? usually it's half hour show so about 768MB of very high-bitrate MPEG2 as my source. I would like to compress that to maybe 256MB...

Also I know what I frames are but what is the difference between P and B frames?

And is there some basic encoding guide...like...should I use more I frames instead of higher bitrate for maximum effiency or what?? what balance of I/P/B is best?

thanks in advance.

[dvd_maniac]

Hi xtknight

I know others will have much more knowledge to share on this but I just thought I'd tell you what I do.

I record Analog NTSC TV using one of my Hauppauge capture devices using S-video connections. I record using it's MAX setting of CBR 12mbits per second and 224kbps audio at 48000khz this gives me roughly 2.5GB per half hour show. I know it sounds a lot bigger than your 768MB but if you plan on shrinking it anyways than the origonal size shouldn't matter, right?
I was told that having more bits to start gives better compression results.

Then I use Nero's Recode to shrink into Standard AVC profile at about 150MB per half hour. If they are shows I really like then I might cut out commercails first using Mpeg-VCR. This should give you pretty good quality, but you can use a higher file size if it doesn't impress you.

You can find an explaination about I, B, and P frames HERE (http://forum.doom9.org/showthread.php?s=&threadid=19436)

Hope this helps a little. If not then good luck...

[xtknight]

ok...thanks.. that helped me a lot. ummm is there a trial for nero recode? i can't seem to find it. i think i downloaded packages 1-3 but i still don't have that program in my start menu...odd.

i guess i'm better off doing some experiments of my own...i might as well post my results here too...

any idea about matrices?

thanks again,
xtknight

[dungweaver]

<snip>

any idea about matrices?



AFAIK the matrices are the 'heart' of the compression (actually, quantization) of mpeg4. Rather than use a generic 'one size suits all' matrix, some smart people have developed - and then fine tuned - matrices for specific circumstances, such as low, medium and high bit rates etc.

I record PAL TV and compress with XviD. Can't see how the NTSC thing would be that different. I currently use VirtualdubMPEG2 and these key settings:

- Sharktooth's EQM V3ULR (revision 3) (http://forum.doom9.org/showthread.php?s=&threadid=83125) matrix
- Single pass (see this thread (http://forum.doom9.org/showthread.php?t=95390) as to why)
- Fixed Target Quantizer of 3 and not a fixed file size
- Resize via Lanczos3 to 592x336

YMMV, but these work for me. Read the 2nd thread re: target being hard drive, not a given number of CDs. Your requirments may be different, so you may go for a target file size and two pass.

Some numbers: a ~1 hour SD digital TV show is about 3 GB when recorded in MPEG2 "DVD" mode. The above compresses it to just over 500 MB, with virtually zero visual quality loss. :D

[dvd_maniac]

I use Xvid to encode some material as well. It is a very easy to use codec when used with AutoGK. Good results without any real learning curve.

There are so many great codecs and settings out there to choose from.
Have you looked HERE (http://www.doom9.org/index.html?/codecs-104-1.htm) at the latest Codec shootout? It will give you some info on what codec will work for "YOU".

[xtknight]

forgive the stupid question but how do I tell XviD to use a custom matrix?