libavc vs xvid

Razorblade2000 · 18th July 2004, 00:45

I can't find a single test on the web... what are your experiences concerning quality and speed?

mikeX · 19th July 2004, 20:21

afaik ffvfw = libavc, so the latest doom9 codec comparison should give you some clues.
i dont' expect the speed comparison to be that accurate though.

spyder · 22nd July 2004, 05:32

In my recent experience(which is still very limited mind you), I have found lavc to be better for video that is really difficult to compress. Where xvid blocks up or becomes icky lavc seems to preserve the image more. Though both codecs still don't work well on these sources without more bitrate. As far as speed, I find xvid to be faster due to the "turbo" mode etc. Just my 2 cents...

Mosu · 25th July 2004, 17:07

Quote:

Originally posted by spyder
As far as speed, I find xvid to be faster due to the "turbo" mode etc. Just my 2 cents...

If you want to compare speed then don't compare xvid's "turbo" mode with lavc's standard options. Compare the speed at which you get equal results, that should be better. Or try to get the highest speed from each codec (although that would mean one pass, no MV, bad macro block decisions etc).

With a lot of advanced options on _both_ codecs you get... well... Sometimes lavc is faster, sometimes xvid (because you can argue that some lavc options do not really yield better-looking results but slow it down a lot).

Just another 2 cents.

spyder · 25th July 2004, 22:51

Well, I haven't yet found a similar option to Turbo in lavc. AFAIK turb disables a lot of options on the first pass that make a very slight difference to quality. If you can do the same in lavc then please tell me how

frodoontop · 26th July 2004, 11:10

Turbo doesn't change the speed of the first pass, but only that of the second pass as far as I know. By default xvid uses fast first pass, which you can disable, but fast first pass has nothing to do with turbo mode I believe.

mikeX · 26th July 2004, 17:37

Turbo has nothing to do with 'Fast first pass', and all in all doesn't offer that much of a speed enhancement.

Quote:

From The Unofficial XviD FAQ
-Turbo ;-): This setting skips some search techniques when using Qpel or B-frames to speed it up a bit. Without those options on it has no effect at all. The impact on quality is negligible.

'Fast First Pass' is a whole other thing, it skips some 'advanced' settings, like VHQ, Q-PEL, Trellis, etc, for which the 2nd pass compensates.

Quote:

From The Unofficial XviD FAQ
-'Full quality first pass':By default XviD switches certain options off in the first pass to speed it up a bit. The options that are switched off are not really necessary for a 'normal' first pass (normal as in: you don't keep it afterwards) and turning them off can increase encoding speed considerably.

The difference in speed between 1st and 2nd pass is substancial if you happen to use these options.

spyder · 28th July 2004, 22:15

Ok, I stand corrected then. I really should keep up with xvid more :/

I guess I was thinking of 'Fast first pass'

shevegen · 29th July 2004, 08:57

Gosh I couldnt even contribute at all due to my limited knowledge. But, i guess, having an up-to-date FAQ about xvid and similar is really important.

18th July 2004, 00:45	#1 \| Link
Razorblade2000 Registered User Join Date: Oct 2001 Location: Germany Posts: 314	libavc vs xvid I can't find a single test on the web... what are your experiences concerning quality and speed?

29th July 2004, 08:57	#9 \| Link
shevegen Registered User Join Date: Nov 2003 Posts: 420	Gosh I couldnt even contribute at all due to my limited knowledge. But, i guess, having an up-to-date FAQ about xvid and similar is really important. __________________ OS: Paldo (Linux) AviSynth for Linux, go go go!

19th July 2004, 20:21	#2 \| Link
mikeX yakisoooobaaa!! Join Date: Sep 2003 Location: Greece Posts: 329	afaik ffvfw = libavc, so the latest doom9 codec comparison should give you some clues. i dont' expect the speed comparison to be that accurate though.

22nd July 2004, 05:32	#3 \| Link
spyder Matroska Developer Join Date: Nov 2001 Posts: 315	In my recent experience(which is still very limited mind you), I have found lavc to be better for video that is really difficult to compress. Where xvid blocks up or becomes icky lavc seems to preserve the image more. Though both codecs still don't work well on these sources without more bitrate. As far as speed, I find xvid to be faster due to the "turbo" mode etc. Just my 2 cents...

25th July 2004, 22:51	#5 \| Link
spyder Matroska Developer Join Date: Nov 2001 Posts: 315	Well, I haven't yet found a similar option to Turbo in lavc. AFAIK turb disables a lot of options on the first pass that make a very slight difference to quality. If you can do the same in lavc then please tell me how

26th July 2004, 11:10	#6 \| Link
frodoontop Registered User Join Date: Jan 2003 Location: Netherlands Posts: 126	Turbo doesn't change the speed of the first pass, but only that of the second pass as far as I know. By default xvid uses fast first pass, which you can disable, but fast first pass has nothing to do with turbo mode I believe.

28th July 2004, 22:15	#8 \| Link
spyder Matroska Developer Join Date: Nov 2001 Posts: 315	Ok, I stand corrected then. I really should keep up with xvid more :/ I guess I was thinking of 'Fast first pass'