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  1. Hi,

    I have an ATI AIW 128 Pro AGP. I installed the iuVCR software,WDM-based and use Picvideo mjpeg codec for my ATI captures. I just can't generate a correctly synced AVI file.

    I tried to capture a 1H30 movie from my satellite receiver (source doesn't matter anyway), picture quality is OK, but the sound is getting more and more desynchronized as the movie plays. I capture 480x576, 25fps (PAL) without any dropped frame.
    After 30 minutes or so, I can notice an aproximate 0.5s delay between audio and video (audio is late), which gets worse and worse until the end of the movie. I'm using a SB live 1024 on a VIA Apollo133 chipset (I know, I did everything to deserve problems). OS is WIN2000 Pro sp1.

    I tried MMC 7.5 with the same desynchro results.

    So, sorry if this has been asked already, but I really can't get anything out of it.
    Is this related to Picvideo codec ? Is there any way I can capture audio and video separately ?

    Please help me out !

    Waldok
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  2. You can set the audio to be the master stream in the latest beta of iuVCR. I don't have all the specifics because there is no English help file yet, but if you write Ivan, he'll hook you up with the proper settings. It should fix all your problems.
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  3. THanks for helping, but I already tried all possible parameters combinations and results are always the same (even worse when I use Audio as Master Stream, which should normally be OK).

    Any othe idea ?

    Waldok
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  4. I have this inreasing desync problem on the DivX captures I do with MMC 7.1 and my Radeon AIW. I capture, and the file starts out synched but the audio slowly falls behind the video as the file plays.

    What I do is open the AVI in VirtualDub. Set Video to Direct Stream Copy and the Audio to interleave interval "every 500 ms" (instead of every frame). I also compress my audio at this point to 96k 44,100kHz 16-bit Stereo MP3 at the same time, because MMC doesn't compress the audio during capture.

    I have also fixed some out-of sync files on which the audio track had already been compressed, also by setting the audio interleave to "every 500 ms" and leaving audio and video set to Direct Stream Copy.

    Either way, save it as a new avi (never overwrite your master file) and best of luck!
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  5. THanks a lot for helping.

    My problem when trying to do as you advice (which I did yesterday) is that my AVI file is about 35Gig ! Although I have a 60Gig hard disk, I already have some stuff on it waiting for encoding so I don't have room enough for duplicating a 35Gig file with Virtual Dub... and I probably never will...

    I'll probably use your method for smaller files though, butg I'd like to find a way to directly generate correctly synched material at capture time. Tonight I'll try to remove my SBLIve 1024 and I'll give my old SB AWE32 ISA a try, just in case it will lighten the PCI bus a bit...

    Other advices are still welcome on this never solved sync issue.


    THanks again to the guys who already answered !

    Waldok
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  6. Member
    Join Date
    Aug 2002
    Location
    United States
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    Hi, this reply is a little late.. But I want to have some reference out there for all future users of iuVCR. I just found out how to mess with audio/video sync issues on this software. As soon as the sync is working properly with iuVCR there really isn't a better TV Capture application out there, IMHO.

    It all depends on what your end target is going to be, and what your operating system is. Do you want to just capture files and watch them once then delete them? Or do you want to capture files and encode them for later use such as SVCD, DVD, etc.

    Just watching them: If you only plan to watch the video and then delete it later.. Or as long as you don't plan to encode it to anything else.. Go into iuVCR and in the options tab click 'Master Stream' and then select audio. This works for every capture. As you capture the file, the software will determine how long the audio stream is in the file. Then, it will change the frame rate of the video so that the video is the exact length of the audio. This is a very simple trick and it works fine to keep the audio and video in sync with each other. The problem here is if you have Windows 98 and you need to segment video files, each SEGMENT of your movie will have a different frame rate. That prevents them from being imported and appended in Virtual Dub. Also, even if you have a single file, the frame rate will be off of what you selected (like 29.9705). This doesn't work when you try to encode them to a fixed rate like 29.97 for DVD, the rate is changed and the audio comes out of sync with the video. Thus, you can only use this to keep sync on files that will not be encoded but only watched.

    Encoding them: If you need to encode them, de-select 'master stream' entirely and then select 'Sync using stream offset'. Then save the template, and close and restart iuVCR. This uses your video card drivers. If you capture and the sync is not working, you need to update to the latest drivers for your card. It won't work with every video device, but should with the newer ones that use WDM and directshow. I believe this uses a feature more like Virtual Dub where it drops video frames to keep the audio and video in sync.. What it means is the captures are in sync and the frame rate is the same in each segment, so you can then encode these files without problem to any other format.

    PS: Using neither of the above (Not using master stream and not using sync using stream offset) is not recommended. The captures will be out of sync. You can decide which method works best for you depending on what your final output will be.
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