Playing full length movies

[rzanology]

Hey guys, I love to watch movies on my Ipaq, but something is really making more of a pain than a treat. I noticed that the movies start to "lag" as the movie goes on. I'd say about 15 to 20 minutes into the movie, the video seems to drop back behind the sound. I know it isn't the ipaq because the frame rate is still very smooth, and when I launch another program, it still responds as quick as it did without the movie playing. Why does this happen? Any solutions?

[syphix]

What are you encoding in? What are you playing with on the PPC? Does it play fine (without the delayed lag) on a PC?

[Buddha]

If you are playing a DivX movie then your interleaving in virtualdub might not be set correctly when encoding.

go to Audio/interleaving/

change:

Interleave every 1 frames to
Interleave every 500 ms

This setting should work correctly on an ipaq if the audio is encoded at 32kbps, 48kbps or 64kbps (or even higher)

[rzanology]

heres the thing. I usualy get movies from kazaa, and just optimize them through windows movie creator 2. It has an option to optimize for pocket pc. But the file plays fine on the computer, ther main reason i do that is because it makes the file smaller.

[GingerTommy]

Buddha, do you know if the interleaving settings are effective for 24kbps audio? I have an exceptionally small one :oops: (storage card!) and go for as much reduction as possible.

[Ekkie Tepsupornchai]

Buddha, do you know if the interleaving settings are effective for 24kbps audio? I have an exceptionally small one :oops: (storage card!) and go for as much reduction as possible.
I could be wrong but I don't see any reason why your audio bitrate should effect the interleaving properties. I'm assuming that you're not trying to change the frequency of the base sound file while in VirtualDub.

Buddha, what's the rationale on changing the interleaving from 1 frame to 500 ms? I've always had mine set to 1 frame w/o issue.

[Ekkie Tepsupornchai]

heres the thing. I usualy get movies from kazaa, and just optimize them through windows movie creator 2. It has an option to optimize for pocket pc. But the file plays fine on the computer, ther main reason i do that is because it makes the file smaller.
What format are these Kazaa movies in? Is it MPEG?

I personally haven't used Windows Movie Creator for movies. If the original format is MPEG, you may want to give a serious look at VirtualDub to handle your conversions. I imagine there are better control settings and more powerful features with the trade-off of slightly higher learning curve. I use it to convert VCD MPEGs all the time without any problems.

[GingerTommy]

I do change the sampling rate from 48000Hz to 44100Hz (as per the pocketmatrix guide) would this effect audio/video sync?

I think I will test the playback on my desktop before blaming it all on VirtualDub, but please let me know about the effectiveness of altering the audio interleaving setting.

[Ekkie Tepsupornchai]

I do change the sampling rate from 48000Hz to 44100Hz (as per the pocketmatrix guide) would this effect audio/video sync?

I think I will test the playback on my desktop before blaming it all on VirtualDub, but please let me know about the effectiveness of altering the audio interleaving setting.
I'm actually not totally positive... Do you do that conversion from within VirtualDub? I do convert my audio as well, but have them converted before using them within VirtualDub. There's an app out there called HeadAC3he that will convert the AC files to WAV (with an option to downmix to 44.1).

Let me know your results.

[GingerTommy]

I'm actually not totally positive... Do you do that conversion from within VirtualDub? I do convert my audio as well, but have them converted before using them within VirtualDub. There's an app out there called HeadAC3he that will convert the AC files to WAV (with an option to downmix to 44.1).

I do use VirtualDub to downmix so maybe that's the problem??? As you report no syncing problems, I will try using HeadAC3he for this operation (I already use it for AC3 - WAV conversion) and see if there is an improvement. Thanks ekkie.

[FieldDoc]

why don't you rip one of your own DVDs from scratch. If there is not an audio problem in this situation, you can bet your bottom dollar that it's simply because you are altering an already altered video file (i.e. someone who posted it on kazaa has ripped it but probably optimised for full screen on a 17 inch or something)

[Ekkie Tepsupornchai]

why don't you rip one of your own DVDs from scratch. If there is not an audio problem in this situation, you can bet your bottom dollar that it's simply because you are altering an already altered video file (i.e. someone who posted it on kazaa has ripped it but probably optimised for full screen on a 17 inch or something)
I assume you're addressing the original poster and not GingerTommy (who is ripping his own from DVDs I believe)?

It doesn't appear to me that the original poster is accustomed to the tools needed to rip movies from scratch (I don't believe that's an option for MS Movie Maker). For many, it's much more convenient to just convert movies already made.

[GingerTommy]

I assume you're addressing the original poster and not GingerTommy (who is ripping his own from DVDs I believe)?

I am ripping my own DVDs and do experience lag as the movie progresses.
I don't think it's my hardware (iPAQ 3760) as I decimate frames and rarely drop any on playback. I am open to suggestions, specifically more info on the audio interleaving setting in VirtualDub. Buddha, any advice???

[Buddha]

I could be wrong but I don't see any reason why your audio bitrate should effect the interleaving properties.

You're totally right, I just mentioned those bitrates as an example because I know they work fine ;) In general there should be no problem with any bitrate.

Buddha, what's the rationale on changing the interleaving from 1 frame to 500 ms? I've always had mine set to 1 frame w/o issue.
Well this is simply an old 'DivX trick/rule' which has been tested over the years and was one the settings yielding the best general results for most movies. I don't even remember exactly why but I think it has to do with the fact that the first (every 1 frame) keeps track of the soundfile frame-based, while the other keeps the audio file in sync time-based (every 500ms). Frame-based interleaving is more 'vulnerable' to errors (e.g. too many dropped frames etc) which can lead to the video and audio getting a-sync.

[Buddha]

I do use VirtualDub to downmix so maybe that's the problem??? As you report no syncing problems, I will try using HeadAC3he for this operation (I already use it for AC3 - WAV conversion) and see if there is an improvement. Thanks ekkie.

I'm not sure if downmixing in Vdub is a problem, never had any problems with downmixing a WAV with it (not AC3 of-course), but it is certainly advisable, even recommended, to make the AC3->WAV->MP3 conversion and downmixing with HeadAC3he or BeSweet before encoding in Vdub.


I am open to suggestions, specifically more info on the audio interleaving setting in VirtualDub. Buddha, any advice???

What I would recommend is to start all over again (just to be sure) and first convert and downmix the audio with one of the mentioned programs to something like 32kbps 22kHz CBR MP3 (or even lower) for example. Then to encode the video to divx separatly (without any audio) in Vdub.

After you have the separate divx.avi and the sound.mp3 then mux (muxing is the process of combining the audio and the video toghether) the files together in Virtualdub:

Download Wavemp3 1.2 (which you can find on www.doom9.org in the download section)

-Open Wavemp3
-Press WAVE!
-select the MP3 you made and press OPEN

Now your MP3 should have a wave-header so Vdub should be a ble to open it correctly

open Vdub
-load the video file with FILE>OPEN VIDEO FILE
-set VIDEO>DIRECT STREAM COPY
-goto AUDIO>INTERLEAVING
-set INTERLEAVE AUDIO EVERY to 500 and change it from FRAMES to MS
-press OK
-AUDIO>WAVE AUDIO
-Choose the soundfile you just made in Wavemp3 (sameasmp3.wav)

-Goto SAVE AS AVI
-give your final movie a name and save it.

Now try it on your ppc and prey it works :D

sidenote:
In the interleaving window in vdub there is another option that lets you adjust the audio delay, this can help you adjust the audio, this works in theory if you would experience the delay while playing it on your desktop because you can then check every change you make to the timing but for a pocketpc movie that would mean having to copy the movie to your pocketpc each time you adjust it, to see if it is in sync. This could take HOURS of copying&adjusting (trial and error) till you go mad and jump out of a window because that's less painful than trying to adjust the delay correctly. :mrgreen:

[Jude]

OR you can just convert the WAV to an OGG Vorbis file (which sounds a lot better at low bitrates than MP3) using any of the free converters out there (Oggdrop, dBPowerAmp, etc.), BeSweet and HeadAche can convert to OGG as well. Then using OggMux (oggmux.sourceforge.net) you load your AVI, then you load your OGG, mux them together and voila! You get an OGM file that has good audio/video synch and better seeking compared to AVI at a slightly smaller size. PocketMVP plays them just fine.

[Ekkie Tepsupornchai]

OR you can just convert the WAV to an OGG Vorbis file (which sounds a lot better at low bitrates than MP3) using any of the free converters out there (Oggdrop, dBPowerAmp, etc.), BeSweet and HeadAche can convert to OGG as well. Then using OggMux (oggmux.sourceforge.net) you load your AVI, then you load your OGG, mux them together and voila! You get an OGM file that has good audio/video synch and better seeking compared to AVI at a slightly smaller size. PocketMVP plays them just fine.
Thanks for the tip... I've been wondering if there was a way to use OGG instead of MP3, but never got around to really looking into it. It's too bad this can't be done directly in VirtualDub. I'm assuming that the Ogg mux is just an interleaving process and there is no additional re-compression?

I'll have to try this soon...

[Buddha]

OR you can just convert the WAV to an OGG Vorbis file (which sounds a lot better at low bitrates than MP3)

Couldn't agree more :D BUT a VBR (ogg) format requires more processing power to decompress than a CBR (mp3) format, so I don't know if its recommended in combination with video for 'slower' ppc's like the 37xx. Anyone tried it yet?

[Jude]

Yup there's no re-compression involved. Muxing just stitches the audio and video together, takes just a few seconds.

I'm using an iPaq 3850 (206 mHz StrongARM) and I can use up to 96 kbps OGG audio (which is near CD quality for most people) and still get 24 fps at 240x176, and up to 20 fps for fullscreen 320x240 (although I prefer decimating to 15 fps at this resolution). Normally I use 32 kbps though and at this bitrate there doesn't seem to be much of a difference in processor load compared to MP3.

And compared to the Xscale PXA250 Pocket PCs, the 37xx isn't really all that "slower". Could even be a bit faster in fact because of the 12-bit screen.