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magoh
28th May 2004, 09:35
Hello everybody

I would want to re-compress (I know this is a bad idea, but I really want to do it) 2 movies and then to burn them on 1 CD.
So each movie must have a size of 350Mo (bitrate between 300 and 350 kbps).

Is there a custom matrix better than H.263 to do that ?
I looked for information on custom matrix and what they are for, but I did'nt find any information on what bitrate they are for (for instance, ultra low bitrate is for a ... bitrate). Where can I find these information?

Thanks a lot

aketon
28th May 2004, 10:16
At this bitrate, h.263 is the best you can use! Do not look for extra details at such low bitrates!

magoh
28th May 2004, 11:06
So, what are the others matrices designed for?
Where can I find more information on custom matrices?

aketon
28th May 2004, 11:32
Why don't you see the custom matrix comparison? http://forum.doom9.org/showthread.php?s=&threadid=76021

Jawor
28th May 2004, 13:07
Originally posted by aketon
At this bitrate, h.263 is the best you can use! Do not look for extra details at such low bitrates!
There is no best matrix for low bitrates. Can't you remember why best settings are a forbidden topic? Because everybody has his/her own best settings.

Originally posted by magoh
So, what are the others matrices designed for?
There are many matrices designed for low bitrates, e.g. Low Bitrate Matrix, Very Low Bitrate Matrix and Ultra Low Bitrate Matrix that are bundled with Koepi's XviD distribution. I added even more matrices to the package with my build (the link is in my sig). I designed a matrix for low bitrates some time ago (look again at my sig :D ).

stephanV
28th May 2004, 13:25
@magoh

a few tips (if you havent thought of this already ;) ):

- take a good look at different resizing filters. keeping the original resolution doesnt seem a good idea to me, so resizing will be essential.

- spread the 'pain' between audio and video equaly. good sound with a lousy video is (for me) no fun to watch, the same holds for the opposite.

magoh
28th May 2004, 16:11
@jawor
- the link on your site to download xvid build are dead... (I'll try later)


@stephaneV
For audio, I hesitate between these format :
- ogg vorbis q = -1 (about 45kbps) : good compromise between quality & size (but my hardware DVD/divx player can't read vorbis)
- divx audio at 64kbps (but I hate WMA)
- lame MP3 at 64kbps (or maybe mp3pro, my DVD/DivX player can play it)


-------------------
Thanks for your help

Teegedeck
28th May 2004, 18:32
WMA is bad beyond words.
At this low bitrate I believe HE AAC is your only option.

SeeMoreDigital
28th May 2004, 23:45
Originally posted by Teegedeck
WMA is bad beyond words.
At this low bitrate I believe HE AAC is your only option. Agreed!

Unfortunately we are still all waiting for Nero's 'parametric' H.264 audio. Which promises high quality sounding audio at low bitrates! But until then AAC-HE is very good. However, if you are using Nero and encoding direct from an .ac3 stream, make sure your output is 2Ch instead of 6Ch.


Cheers

bond
29th May 2004, 11:04
Originally posted by magoh
or maybe mp3pro, my DVD/DivX player can play itevery mp3 player can play mp3pro (like every lc-aac player can play he-aac), but not with the full quality!

Originally posted by SeeMoreDigital
Unfortunately we are still all waiting for Nero's 'parametric' H.264 audio. Which promises high quality sounding audio at low bitrates! But until then AAC-HE is very good.sbr and ps dont exclude each other! you can use both together (and play them in every lc-aac player, still to make use of the full quality you will have to use a decoder which handles the special info stored by ps and sbr)

SeeMoreDigital
29th May 2004, 11:34
Originally posted by bond
every mp3 player can play mp3pro (like every lc-aac player can play he-aac), but not with the full quality! I have to admit I'm a total convert to AAC-HE.

I used to use mp3pro at 96kbps to back-up my audio CD's but it sounds crap when played back via a non mp3pro player. AAC-HE at 96kbps fairs much better in this regard.


Cheers

kilg0r3
29th May 2004, 15:30
Originally posted by Teegedeck
WMA is bad beyond words.
At this low bitrate I believe HE AAC is your only option. Hrrrm, pehaps I am missing something, but if he uses the new aoTuv vorbis builds, hell get very good quality at very low bitrates. IMO, qualitywise, there is no need at all to use AAC-(HE).

Jawor
31st May 2004, 20:42
Originally posted by magoh
@jawor
- the link on your site to download xvid build are dead... (I'll try later)
:stupid:
Sorry, guys, it won't happen again (I hope :D )

Thanks, magoh.

Asmodeus
31st May 2004, 21:31
If I may put my 2cents or 3grosze (;)), I sugest VP62 (Hightend profile) two pass encode, resolution not biger than 512xsomething. It's pretty good, but slow. Blured image is at this point an advantage. That's my opinion.

Jawor
1st June 2004, 15:36
Originally posted by Asmodeus
If I may put my 2cents or 3grosze (;))

I think I got your point. Soon this will be a Polish-only club :D

Originally posted by Asmodeus
Blured image is at this point an advantage. That's my opinion.
Many people like sharp resizers (e.g. Lanczos) and sharp matrices (e.g. HVS - Best Picture) even at very low bitrates, at least when compressing with XviD. I'd try 512xXXX resized by LanczosResize().

lithoc
1st June 2004, 18:53
There's aoTuVb2(beta 2) available if you seriously considering low bitrate. You can use -q-2 (which is not in standard vorbis but it works with any vorbis decoder). This will give bitrate around ~40kbps.

For advance user, you can try

--advanced-encode-option lowpass_frequency=16*

* = khz

Which default -q-2 is 13.9khz which some of you might not like it.

I've test on some music encode using -q-2 and suprised with the actually at this bitrate.
Well, it's certainly not audiophile quality but still acceptable.
Hopefully it will fulfill your need(2 movie 1 cd).

Asmodeus
1st June 2004, 21:25
Originally posted by Jawor
Many people like sharp resizers (e.g. Lanczos) and sharp matrices (e.g. HVS - Best Picture) even at very low bitrates, at least when compressing with XviD. I'd try 512xXXX resized by LanczosResize().

Yes. I like sharp image very much :D But sharp picture contains many Gibbs effect artefact (mosquito noise) which I do not prefer.
And by low bitrate I mean less than 300kbps :devil:

-----------------------------
Poor english team memer :sly:

Blue_MiSfit
2nd June 2004, 11:22
lest we forget about the compresability gains to be found with denoising? perhaps a twist of PeachSmoother or PixieDust would be nice to chill the video out a little and make it compress better.

Definatley lots of bvops, I would suggest a sensitivity of 80, and a setting of 8/1/0. I have read forum postings regarding this setting, and was able to reproduce it in my setup.

quant matricies - I would try the "low bitrate matrix" from kopei's build. Also encode with h263 quantization, and compare.

Audio - VORBIS. Especially the latest developments as mentioned in previos posts. I don't like AAC personally, but thats just an opinion. Vorbis seems to scale the best to my ears, but do some comparison encoding, figure out which format sounds better to you. HE-AAC might be awesome, but Q2 vorbis will smoke it IMHO ;)

This is definatley do-able.

Jawor
2nd June 2004, 15:27
Originally posted by Blue_MiSfit
Definatley lots of bvops, I would suggest a sensitivity of 80, and a setting of 8/1/0. I have read forum postings regarding this setting, and was able to reproduce it in my setup.
You can use even 100 B-frames if you want to :D
I managed to force the usage of 100 B-VOPs by setting B-VOP Sensitivity to 10000 and BVOPs to 100 / 1.00 / 0.00. But I wouldn't recommend this - it looks really ugly. It's better to stick with less than 10 B-VOPs.

Originally posted by Blue_MiSfit
Audio - VORBIS. Especially the latest developments as mentioned in previos posts. I don't like AAC personally, but thats just an opinion. Vorbis seems to scale the best to my ears, but do some comparison encoding, figure out which format sounds better to you. HE-AAC might be awesome, but Q2 vorbis will smoke it IMHO ;)

Yeah, I agree with that. Usually I use Vorbis audio encoded with Q=2 in my 1CD-rips and it sounds OK.