Divx with AC3 gives choppy playback

[Nestor Cantibus]

Hello,

All my movies (dvd and divx) give excellent picture BUT divx with AC3 sound gives a choppy playback. I tried a couple of AC3 codecs (standard and Odio Dekoda). Also tried different divx codecs (divx 3; 4.2; 5.02). Tried BSplayer, windvd and mediplayer 6.4 and 9. All gave same problems. My cpu usage is always under 100% (bsplayer even 50%) with AC3 movies and problem stays. I tried to use onboard sound instead of SBLive and vice versa but problem remained. When I unregister the ac3 codec (no sound) playback is smooth. So the divx seems ok. I have this problem with all AC3 divx movies. What can it be??!!?

Has anyone got a suggestion?!?!

My config:
Athlon Xp 1700
Matrox g450
soundblaster Live Value
G400 filter
Divx 5.02
Odio Dekoda (ac3)

Thanx, Bob

[setarip]

1) Make sure hardware acceleration is on and set to "Full"

2) If necessary, install DirectX

3) If problem occurs only with regard to videos playing from DVD or CD drive, if available, turn on DMA

[Nestor Cantibus]

1) I am using windows XP and xp hasn't got that setting anymore or I just cant find it right now.
2) Xp comes with direct X and I upgraded it to 8.2 (Changed nothing)
3) DMA is on on both Hd's and both cddrives

Thanx

[Batman]

Consider using an alternative ac3 decoder, such as the intervideo ac3 decoder available in the TSUNAMI CODEC PACK.

[setarip]

"1) Make sure hardware acceleration is on and set to 'Full'"

Check to see if it's available in the Windows Media Player under "Options"...

[Nestor Cantibus]

Well I uninstalled Odio Dekoda and installed Intervideo AC3 decoder from tsunami codec pack but playback is still choppy (odio gives a little bit better playback)

And I checked the hardware acceleration and is was set on full

[setarip]

In re-reading your initial post (I must have misinterpreted your reference to "DVD and DivX" as meaning BOTH were "choppy" due to .AC3 audio), I would speculate that the SOURCE of the problem is the (undoubtedly) downloaded files. Are the "problem" files from the same source?

If your DVDs (the vast majority of which are .AC3 encoded) play properly, then there can't be a problem with the .AC3 decoder (IVIAUDIO.AX for WinDVD).

[Hydrogin]

Hi there! This is my first-ever post to this forum. Hope this helps :)

My friends and I have some relevent experience trying to view AVI files that are encoded using DivX video and AC3 audio (Dolby Digital). We are running WinXP Home, have loaded the latest DivX codec (the DivX 5.0 bundle) and are using the DirectShow AC3 filter from Nimo's Code Pack (v5.0, build 8). Our PC's are run-of-the-mill Athlon 1800 rigs.

What we have noticed is that playback using Media Player 8.0, which is the version that comes bundled with XP, is indeed "choppy". Certainly not smooth like when we play a DivX video that has an MP3 audio stream.

However, when we simply switch to Media Player 6.4 using the same AC3 filter/codec, the playback is smooth and normal! I have seen this happen on a number of WinXP PC's. So, there is a practical solution for XP users - WMP 6.4 is located at:

C:\Program Fiiles\Windows Media Player\mplayer2.exe

What I'd like to know is, why is this the case?

I have not been able to contact Nimo to ask. Is it somehow related to the filter implementation? Perhaps the version of DirectShow used to create the filter needs to be updated to a newer version to work more efficiently with WMP 8.0?

Hydrogin

[Hydrogin]

I forgot to mention, I use Phillipe Duby's great little utility to tell me what codecs/filters are loaded on my system, and to tell me how the video and audio streams are encoded in a file:

http://avicodec.duby.info

AVIcodec tells me that the two AC3 filters I use from Nimo's Code Pack are:

AC3 from AVI Xform, v2.20, decaudio.ax
AC3 Prologic Decoder, v2.20, ac3audio.ax

I'm not sure if one or both filters are used in playback, especially since I thought Dolby Digital 5.1 and Dolby ProLogic were different encoding schemes. But hey, I just know enough to be dangerous, not an expert :)

[setarip]

Although it is common knowledge (at these forums) that Win Media Player v.6.4 is the "best bet" for virtually any video format versus all subsequent versions of Windows Media Player - proving that newer is not necessarily better in the world of software - this can't be the sole resolution to the problem stated by Nestor Cantibus, who indicated that the same playback problem exists when playing .AVIs with .AC3 audiostreams under WinDVD...

[Hydrogin]

Setarip,

Yes, thanks for the correction. I didn't read the original post carefully enough (its late here!) where it was stated that the problem existed with *both* WMP 6.4 and 8 in addition to other players.

Still, I'd like to know more about the question I posed concerning the different playback results between WMP 6.4 & 8.0 when using the AC3 codec from Nimo's Pack. I hate to leave it as "WMP 6.4 is more robust than 8.0" w/o digging more. Perhaps I'll post it as a new thread.

Hydrogin

[Nestor Cantibus]

To answer a couple of questions:
- The problem occurs only with Divx and Not with DVD
- When I play divx with ac3 with windvd there's no audio (default no ac3 codec installed on my pc). Only when I install a thirthparty/external ac3 decoder

[setarip]

What you have just stated appears to be illogical:

If DVDs (which typically contain .AC3 audiostreams) play properly (including audio) under WinDVD, then WinDVD's .AC3 filter (IVIAUDIO.AX) MUST be properly installed as part of the overall WinDVD program.

Therefore, if WinDVD plays your .AVI silently, the problem cannot be the .AC3 audio filter.

What version of WinDVD are you using?

Out of curiosity, please do the following:

1) Load the file into VirtualDub

2) From the "File" dropdown menu, select "File Information"

3) Post (here) EVERYTHING you see (both video and audio information), or post a screen capture .jpg of the information box

[Nestor Cantibus]

Well Windvd plays avi's in a mediaplayer based environment so it works the same as mediaplayer (for avi's). I used windvd 4.0 and the new 4.5 (platinum). BUT I found the solution. I muxed 2 avi's with ac3 stream and when I followed the advice of setarip:
http://forum.digital-digest.com/showthread.php?s=&threadid=13778
AC3 192Kbps - Preload 80ms Interleave 80 ms

AC3 384Kbps - Preload 160ms Interleave 160 ms

AC3 448Kbps - Preload 128ms Interleave 128 ms

The problem was gone. I just wonder why all my ac3 avi's are wrongly muxed. And why doesnt anybody else have this problem??
I attached the file info

[Nestor Cantibus]

After Muxing this is the file info:

[setarip]

"when I followed the advice of setarip"

I'm glad to hear that my advice (based on UncasMS' information) contributed to resolving your dilemma ;>}

As to why you've been running into this problem:

If you're dealing with multiple downloads from the same source, the creator of the file probably has insufficient knowledge about the proper settings for the .AC3 audiostream

If YOU'RE creating the files, well... ;>}

P.S. - As I stated before, it couldn't have been a problem with the .AC3 filter/codec...