Newb h264 or codec advice request

[EAO]

Finally started to branch out from .vob, .mpeg and basic .avi codecs. I'm a late bloomer and have only played with .mp4 and .xvid over the last 2 months.

The compression ratio and quality is very impressive vs. .mpeg.

For the first time ever I downloaded some BBC .avi (extension) videos that I believe are .xvid. They are approx 330 MB in size and 42 minutes long (Dr. Who eps) and if I recall (640 x 306 or something close to that) They play fine and look fantastic on my 642.

I know a lot of quality is from source material but i have not been able to achieve this quality at that size in the xvids I have created. I've been converting .vob into .avi using Nero Recode 2 pass - std option, then reprocessing the audio track only into .mp3 (So video is only being converted once) My files 42 minute files are approx 430MB at 624x384 and at 1.35 Mbps.

Is it possible the Dr Who .avi's are a different codec like .H264? (I would like to understand how this level of quality was achieved as it looks like the best DVD's I have ever played and I know their original source was off the BBC TV.) How can I tell?

[jagabo]

GSpot, AVICodec, MediaInfo. Most of the new Dr Who AVIs I've seen are Xvid.

[redwudz]

You can drop them into Gspot 2.70 to see the bitrate and codec used. If it was H264 it wouldn't likely play on a settop player.

[EAO]

Thanks for the info. After I see what's up - I'll post.

Wow. It's xvid!! I wonder if the original source was off a high def TV. It is simply stunning. I have got to figure out this technigue.

My DVD Rips look just as nice - but are much bigger. My Dish Network rips are terrible compared to it.

Time for a lot of testing... I guess.

[jagabo]

The new Doctor Who episodes are from direct downloads of the 720x576 MPEG2 satellite data.

[celtic_druid]

Nero's MPEG-4 encoder although faster I still don't think is as good as Xvid.

[EAO]

I beg to differ... somewhat. My DVD Rips look just as nice compared to the Dr. Who's I mentioned - and are much faster than traditional xvid conversion. The size is what astounds me. The Dr. Whos are twice as small and still maintain an incredible image.

I have processed xvids using other tools and they look no better than DVD Recode (using standard two pass).

Frankly - given the quality equivalent - I will give up the size issue before I go back to taking well over twice as long to convert. I can recode a 2 hour movie (2 pass) in under a half hour and then only have to add about 10 minutes to convert the audio to mp3. Total time is about 45 minutes vs. 3+ hours using other methods.

I also did not realise the source was of such high quality. Given the BBC voice over promo's at the end of each episode I assumed it was SD Quality from source. Seems the U.S. viewing public is getting the 'short end' on quality yet again.

[celtic_druid]

Well if the source is 720x576, then it is SD. Same res as a PAL DVD. Your results would seem to concur with what I said. You are encoding faster, but with lower quality (compensated by a larger filesize).

[jagabo]

The Xvid Doctor Who episodes you are downloading probably come from Captian Jack or Exterminate who post regularly at alt.binaries.drwho. You can ask them how they perform the Xvid conversions. I suspect they are either using AutoGK or VirtualDub (Mod or MPEG2). Scheherazade usually posts the MPEG2 sources if you want one to try your own conversion. The latest episode was posted yesterday.

[Midzuki]

I know a lot of quality is from source material but i have not been able to achieve this quality at that size in the xvids I have created. I've been converting .vob into .avi using Nero Recode 2 pass - std option, then reprocessing the audio track only into .mp3 (So video is only being converted once) My files 42 minute files are approx 430MB at 624x384 and at 1.35 Mbps.

Maybe I'm wrong, but I suspect the XviDs you have downloaded
were encoded with some well-known custom quantization matrix.
Can Nero Recode import CQMs?

=====

[EAO]

Not that I'm aware of.

But if the matrix work's with autogk i'd like to give it a spin. Any link where I can find what you're talking about?

BTW I stand corrected (obviously) regarding my SD remark. WHat I meant by SD was the lousy sat output (Dish) somewhere in the area of 480x480 (maybe)... a lower form of SD one might say.

[Midzuki]

http://forum.doom9.org/showthread.php?s=&threadid=72679 says:

7.1 What matrixes (CQM) does AutoGK uses?
- in the ESS mode, it uses the H.263 and MPEG standard MPEG4 matrixes
- in the MTK or normal mode, it uses the Jawor1CD CQM (soft matrix)
or the Sharktooth Eqm_V2 (sharp matrix) whenever possible.

More info about the endless subject "xvid cqms":

http://forum.doom9.org/showthread.php?s=&threadid=83125

Have fun! ^_^

==============================================

[EAO]

Thanks. I'll check out that thread.

Perhaps a different thread. Would you have any opinion on the visual diff in quality bet Sharktooth Eqm_V2 and ESS mode?

celtic_druid: I am testing autogk now. I humbly admit that the quality is impressive. It is slower but not too bad as some I've used. It's running right now and Task manager is pinned to 99% on my dual core. It took 27 minutes to transcode a 23 minute DVD extra (512 x384 4:3 output) and it looked very good.

Still have to play with sharpness and check again if I can adjust mp3 volume. Even with normalization - it's a tad low (I'd say 20% too low).

[celtic_druid]

AutoGK uses a 1.2 Xvid build. Other apps may be using 1.1x builds in which case you would get closer to 50% usage on a dual core setup.

[Soopafresh]

Still have to play with sharpness and check again if I can adjust mp3 volume. Even with normalization - it's a tad low (I'd say 20% too low).


You can run the AVI through the Avi_Gain script to bring the volume up.

https://forum.videohelp.com/topic314909.html