Audio out of sync when encoding. Help! :(

[Dreath]

Ok, I've done a little VCD work but this is the first time I've tried to edit out the commercials from a TV show I captured using the ATI TV Wonder card. It captured in the usual MPEG1 format without a problem and plays just fine; no problems.

Now, here is the problem. I want to edit out the commercials so I used Ulead VideoStudio 6 (latest patch) and then re-encoded it using the original file's settings. The resulting MPEG starts out just fine but two minutes into the show the audio is lagging the video by about 0.5 to 1 second. This seems to happen even with a small file segment. I've tried various bit rates and setting in VideoStudio but nothing works.

Is this a problem because the TV Wonder uses a hardware MPEG encoder? If so, why does the original video play just fine but after encoding it through VideoStudio the sync problem occurs?

Please help! Thanks!

Dreath.

[GreyDeath]

MPegs really aren't for editing. I would suggest capturing in the DV AVI (or Huffy) codec, it's alot of harddrive space, but it's takes care of alot of the hassles with editing mpegs. I have a RAIDed 160gb drive and another 120gb for DVD image storage.

I have a Canopus ADVC-100 firewire box and import video using Windows Movie Maker. I then use Tmpgenc to put it into DVD mpeg-2 format, editing out commercials, making picture adjustments (the Canopus box, even though it's cool that it has a A/V sync lock on it, the picture tends to be a bit dark for transfer to DVD.) and increase the audio volume a tad.

A word of caution about TMpgenc, when using the Mpg merge feature, keep it to only 3-4 clips. I've noticed that the sound gets out of sync when you splice together more than that. I've noticed this when putting some 30 mpg2 segments together, the audio starts to get out of sync near the 2 hour mark. Anyone else notice this?

[Dreath]

Thanks for the tip however I want to use the ATI software since it works like a VCR; recording programs when I'm not at home. The advantage is that the hardware encoder is very fast (almost no frames dropped) unlike some software encoders I'm using (might need a faster system). The drawback is that it only encodes in MPEG1 format at a bit rate of 1045kbps. It's doable for what I want to do right now.

Hmmm, would changing the video format from MPEG1 to AVI, editing out the commercials, then encoding back to MPEG1 solve the problem? I'm trying to do this with as little hassle as possible and keeping the video files under 4 gigs. Thanks!

[KingJohn]

Each program your using is probably changing the bitrate, they all have their own idea to what the standard should be for a mpeg 1 VCD. It would be a lot easier to save as AVI, then convert the final product

CBR 1150kbps is for VCD, use anything higher and the programs that convert it, may make a mess of things.

[Dreath]

I kinda figured something like this so I checked the original MPEG1 file and it was encoded at a bit rate of 1048 kbps. I think VideoStudio was trying to encode it at 1150kbps but I could go into custom settings and change that rate back to the original 1048 kbps. This still didn't solve the audio/video sync problem. I also tried to change the bit rate of the audio. This also didn't work. Errr, this is frustrating...

[cmiller173]

Dreath, I think what KingJohn was implying is that ATI is capturing at less than the standard 1.15Mbps. You can use the "ATI AIW MMC Reg Tool" or "ATI AIW MMC 7.5/7.6 Reg Tool" as appropriate to easily tweak the ATI settings since the little slider bar in the ati settings screen doesn't have the fine control to let you hit that number exactly. You can get them in the tools area. I'm currently capturing VCD at 2.0Mbps and I sometimes(but not always) get sync issues after I edit out commercials with TMPGEnc. But at 2Mbps I get pretty good picture quality and the file size is 650-700M for a typical 1 hour episode with the commercials removed. And most importantly 2Mbps works on the standalone DVD player.

[Dreath]

Thanks! I'll give the tool a try. I'm currently looking at the demo of PowerVCR to see if it will do the job for me. Still working on that.

In light of the bit rate issue, I noticed that ATI's default VCD setting uses a bit rate of about 1048 kbps. Quesion is, if it's encoded at 1048 kbps and I go and edit it, do I have to save it at the same rate or can I change it? Can you change the bit rate after you have edited a MPEG1 file without any problems?

I'm still new to this so the concept of bit rate and changing it while editing and then re-encoding is still somewhat new to me. Any additional info would be helpful as I work on this problem. Thanks!

[KingJohn]

I have found many programs with bitrate set at 1150, but in reality they produce 1150,553 or something this can easily be corrected by streaming a copy though TMPGEnc Merge&Cut selecting MPEG 1 VCD from the drop down list. That takes only a few minuets, However with much higher bitrates, I would think that this would cause sync problems.

I would try and capture close to the final format, bearing in mind, the mpeg 1 VCD were not designed to be edited later, and capturing may have dropped frames, any form of edit my introduce lip sync.

[Dreath]

Thanks for the tip. I think I might have figured out a way around this though. I can encode a MPEG1 file using the ATI MMC VCR feature using a custom setting instead of their default VCD setting. I recorded about 3 minutes of video without any loss. Using TMPGenc, I was able to edit the video without any problems or lip sync issues! Woot! Of course, that was only on a 3 minute video segment. The real challenge will be on a 1 hour broadcast. We'll see what I can get with that. Of course, it took me this long to find out how to edit the video with TMPGenc.

Still, it's rather screwy that MPEG is supposedly an industry standard yet each video editor/capture program seems to handle it differently. Errrr

[Dreath]

ACK!!!! It didn't work. Aparently the longer the video is, the more of a audio sync problem you get when you edit out the commercials. Of course, it's a gradual audio sync issue and I'm not going to extract the video and audio like one tutorial says to do on this site. Too much work.

However! I did find a way around this. Using the ATI MMC VCR program, I recorded an hour TV show without a problem. I then used the trimming function of PowerVCR II instead of TMPEGen to remove the commercials. This WORKED!!!! There is no audio sync problems!!! Whoot!

The only drawback was that I encoded at the wrong bit rate (1500 instead of 1150, DOH!). Re-encoding with TMEPGen fixed the bit rate problem so I was able to burn a VCD. I haven't tried the new VCD yet but since the video was fine before I burned it using Easy CD Creator 5, it should be ok when I view it on my DVD player.

Me so happy! Thanks for all your tips!