DivX 5.02 stutters once every second...

**Enchanter** · 25 Aug 2002, 09:14 PM

Actually, a video at a full resolution of 720x576 and encoded at a very high bitrate of 2000kbps is enough to "stun" even a 2GHz system. This is even more so if playback filters are enabled.

If you are trying to achieve maximum quality, you'd be better off using the 1-pass, quality-based setting and setting the quality at the full 100%. Reducing the resolution to 640x() is always a sensible thing to do as well and there really is not much noticable visual difference, apart from the very likely possibility that your system is now not stuttering in the playback anymore.

**Till** · 25 Aug 2002, 10:27 PM

well, i see what you are mean, but some videos work perfectly well at that resolution...according to the DivX 5.02 spec., even HDTV resolutions are supposed to run smoothly with a P4 over 2GHz...i can try to re-encode at less, but even the streams i encoded at 1200Kb show the same behavior...there are a couple of files that i encoded at 720x320 1200Kb (2.25:1) that show this as well...i am not sure that the rendering speed through the player is the culprit.

does 1 pass Quality based really compare to 2 pass encoding? even in high motion sequences? if so, i'd be relieved, since 2 pass is really a drag...i mean with VirtualDub's Batch encoder it's OK, but it seems like one step too many.

**Enchanter** · 25 Aug 2002, 10:37 PM

Originally posted by Till
well, i see what you are mean, but some videos work perfectly well at that resolution...according to the DivX 5.02 spec., even HDTV resolutions are supposed to run smoothly with a P4 over 2GHz...i can try to re-encode at less, but even the streams i encoded at 1200Kb show the same behavior...there are a couple of files that i encoded at 720x320 1200Kb (2.25:1) that show this as well...i am not sure that the rendering speed through the player is the culprit.

does 1 pass Quality based really compare to 2 pass encoding? even in high motion sequences? if so, i'd be relieved, since 2 pass is really a drag...i mean with VirtualDub's Batch encoder it's OK, but it seems like one step too many.

Hmm. That would mean the problem lies elsewhere. Here's what. Play the "stuttery" video and press Ctrl-Alt-Del (I will assume you are running either Win2K or XP) and go to Task Manager. Under the performance tab, does the CPU usage constantly remain at 100%? If so, it is a sign that the system is having a hard time decoding the video. If not, we'll have to look elsewhere for the culprit.

Given your priority for quality over compression, a quality-based 1-pass encoding at 100% quality will indeed be the path to take, and it will indeed save you a considerable amount of time as well.

**Till** · 26 Aug 2002, 12:40 AM

allright, mate...i am going away for 3 days (up to Munich), so i will put 8 movies into the queue for re-rendering at 1 pass 100%...let's see how that works...

i looked at the Performance Monitor when playing one of my 720x576 files, and i was at 55-65%...no problem there...i did notice that i was playing one of the non-audio versions, which appeared to run fine...maybe something gets scewy when interleaving the audio into the file, that causes video to catch up to audio once every second? dunno...

i also decided not to rescale while encoding...i tried to get everything into pretty sizes, but realized that rescaling is unneccessary when doing this for archiving...i do crop out all black space and make sure it's multiples of 8 for DivX 5.02...but re-scaling could only make things worse when i am trying to go full-rez, right?

whoa, just encoding Toy Story 2 and am seeing that it will come out to about 2.5GB WITHOUT the two audio tracks...yikes!...that's about 4Mb/s...if it's anything like other codecs, then maybe going to 80-90% should be almost as good, while saving a LOT of space...what do you think?

well, gotta run...i'll check in again when i'm up in MUC...

**techno** · 27 Aug 2002, 09:01 PM

wooooooooooooooooooooooooooooooooooooooooooooooow @ Enchanter -

maybe something gets scewy when interleaving the audio into the file, that causes video to catch up to audio once every second?

When any file player plays a Video file, it plays the audio file too (if any) and you may notice the stutters etc... as it is doing alot of work, trying to keep the audio and video going smoothly, however, if you only play the audio OR video sepratly - less work, therefore it just plays it.

See where I am going with this?

Techno

**Till** · 27 Aug 2002, 09:22 PM

i don't know where you are going with this...

are you trying to tell me that playing the interleaved audio is taking up the remaining 40% of my P4 2.2GHz processor and then some? i don't think that this is a likely scenario...i continue to believe that my problem is not processor related...if i were trying to decode an HDTV resolution file, i'd believe it...but not a PAL resolution file.

but thanks sfor your hints anyway

**techno** · 27 Aug 2002, 10:00 PM

no no no no....I am not saying there is anything wrong with the processor....

hmm...let me somehow re-think this....

it's hard explaining...eaiser done than said sorta thing..

**khp** · 28 Aug 2002, 02:08 AM

Re: DivX 5.02 stutters once every second...

Originally posted by Till
BTW, i am encoding to MP3 192Kb/s, interlaced every 500ms...sound, however is in perfect synch without stuttering...could there be some issue there? since i am interleaving two soundtracks (English and German), i am using simple MP3 maker to batch process my .wav rips, and then use NanDub to embed the two streams into the .avi file...

If understand you correctly, you don't have any problems if you only use a single audio stream.

Are you not using the morgan stream switcher, for the two stream avi file ?

get it here

Morgan Stream Switcher

http://www.divx-digest.com/software/stream_switcher.html

Download software for playing and making DivX movies

**Till** · 28 Aug 2002, 08:51 PM

yes, i am using Morgan Stream Switcher...i haven't checked yet whether the stutter is unique to the single audio stream versions of my files...maybe that does have something to do with it...

wait, NO...now that i think about it: i have encoded Yellow Submarine, which only has one language embedded...and it does also exhibit the "once a second" glitch...back to the drawing board.

**khp** · 28 Aug 2002, 09:15 PM

Originally posted by Till
yes, i am using Morgan Stream Switcher...i haven't checked yet whether the stutter is unique to the single audio stream versions of my files...maybe that does have something to do with it...

wait, NO...now that i think about it: i have encoded Yellow Submarine, which only has one language embedded...and it does also exhibit the "once a second" glitch...back to the drawing board.

OK, then I would suggest, that you try to downsample the audio to 44.1khz. On an avi file you should be able to do this in virtualdub. On a audio only file, you should be able to do it with besweet + GUI.

Which sound card are you using ?

**Till** · 28 Aug 2002, 11:49 PM

i am using an SIS chipset with onboard audio (forgot the version number) and also an iMic USB audio adapter...i have disabled onboard audio, because it is so noisy, but maybe should try to enable it to see whther i get the same behavior with the onboard chip...resampling to 44.1 is something i would have wanted to avoid, but i have had the same thought as you suggested...

when i get back to my computer, i shall do just that and see.

**khp** · 29 Aug 2002, 02:25 AM

Originally posted by Till
i am using an SIS chipset with onboard audio (forgot the version number)

This is almost cirtainly the problem then. Why not get a nice SB live card, they are not that expensive, and handels 48khz audio stream properly.

**Till** · 29 Aug 2002, 02:43 AM

are you saying that certain cards/devices can handle 48kHz sampling, but doesn't handle it properly? that they play the audio, but cause the video to stutter once a second to "catch up"?

i was aware that some cards cannot handle 48kHz, but i thought that those cards don't play the audio at all then...

well, i will see what happens...maybe the drivers from http://www.usb-audio.de will work differently if i find that the WinXP USB Audio drivers that automatically support the iMic (and which i am using presently) are at fault...

lots of little details to consider...

PS:

i only have two PCI slots in my computer, which are both used by cards that i direly need (a UAD-1 DSP effects card, and a Colorgraphics 4 monitor video card)...so giving one of them up in favor of an SB-Live is not an option...i do, however, also have a MOTU 896 Firewire interface that handles audio at all sampling rates correctly...i shall try that as well...

**khp** · 29 Aug 2002, 08:09 AM

Originally posted by Till

i was aware that some cards cannot handle 48kHz, but i thought that those cards don't play the audio at all then...

No, I think what you are experiencing is pretty much in line with a card that doesn't handle 48khz. The audio card tries to play the 48khz stream at 44.1khz, this means that the audio is playing too slow compared to the video, which then causes stuttering when the player tryes to sync the audio and video.

DivX 5.02 stutters once every second...

DivX 5.02 stutters once every second...

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