Problems with audio sync when editing TyTools MPG with AC3

[LiQiCE]

I've been recording my videos on my Philips DSR7000 with Dolby Digital turned on. The videos that I've extracted from TyTools are a Multiplexed MPG file with Dolby Digital 2.0 384kbps.

I'm trying to edit out the commercials and burn the videos to disk ... Is there anyway I can do this? When I use MPEG2VCR to edit my videos, the audio loses sync with the video. I tried to de-multiplex the video/audio and transcode it into another format using BeSweet (then multiplex it again) but I haven't had any luck with that so far.

Has anyone been able to edit a Multiplexed MPEG video with AC3 for the audio? Please let me know what program you're using (and what version). Thanks for the help!

[Pro-289]

You can't just edit out the commercials using TyTool's GopEditor? It has worked for me in the past with DD audio. When I messed with demuxing DD audio, I had used TMPGEnc to demux, then used BeSweet or HeadAC3he to convert the DD audio to Mpeg, then used TMPGEnc to mux them back.

But the trick I had to use was using the original .MPG file for the video, and the newly created .WAV for the audio. When I tried using the .M2V and .WAV to mux back, I lost sync. But using .MPG and .WAV kept perfect sync. I had done all this in the past for making an SVCD. So I had to convert DD to Mpeg. But this was one way I found that would keep sync in TMPGEnc while remuxing.

[LiQiCE]

Originally posted by Pro-289
You can't just edit out the commercials using TyTool's GopEditor? It has worked for me in the past with DD audio. When I messed with demuxing DD audio, I had used TMPGEnc to demux, then used BeSweet or HeadAC3he to convert the DD audio to Mpeg, then used TMPGEnc to mux them back.

But the trick I had to use was using the original .MPG file for the video, and the newly created .WAV for the audio. When I tried using the .M2V and .WAV to mux back, I lost sync. But using .MPG and .WAV kept perfect sync. I had done all this in the past for making an SVCD. So I had to convert DD to Mpeg. But this was one way I found that would keep sync in TMPGEnc while remuxing.

I dunno, when I tried using the TyTools GopEditor, it didn't seem to be 100% frame accurate. I used it and when I burned it onto DVD, I'd get the first sec or two of a commercial and then it'd cut to the last sec or two of a commercial... With MPEG2VCR it looks like I get frame accurate cuts..

I'll try what you said using TMPGEnc / BeSweet ... Do you know what format in BeSweet I should choose for the MPEG Audio? I tried converting the MPA file I had to WAV and it got all sorts of sync errors..

EDIT: Oh I just checked and I remembered why the GOPEditor wouldn't work for me either ... When I went to make the KEY file in TyTools, it says PTS Reset detected, and it just sits there eating up 100% of my CPU ... I let it run for over 12 hours once and it never finished, so I figured something isn't right.

[captain_video]

GOP Editor is not frame accurate. While you may be able to get frame accurate cuts with MPEG2VCR there are other issues that may occur when editing a ty file. TyTool is specifically designed from the ground up to handle the idiosynchracies of ty files whereas commercial editing programs are not, especially when it comes to Dolby Digital soundtracks. TyTool will handle AC-3 audio just fine without loss of synch but your edit points may not be dead on like they will with MPEG2VCR. However, they should be close enough to have a quality video clip with maybe a fraction of a second of spillover at some cut points.

[LiQiCE]

Originally posted by captain_video
GOP Editor is not frame accurate. While you may be able to get frame accurate cuts with MPEG2VCR there are other issues that may occur when editing a ty file. TyTool is specifically designed from the ground up to handle the idiosynchracies of ty files whereas commercial editing programs are not, especially when it comes to Dolby Digital soundtracks. TyTool will handle AC-3 audio just fine without loss of synch but your edit points may not be dead on like they will with MPEG2VCR. However, they should be close enough to have a quality video clip with maybe a fraction of a second of spillover at some cut points.

Any ideas about the PTS Reset that I get when I try to create the KEY file? This wouldn't be a big deal if I didn't delete the video off of my TiVo already (I could most likely just transcode the audio while I'm extracting it) ... But its already gone, so I'm trying to work with what I've got.

[Pro-289]

Are you using the latest TyTool version? It's at 8r3 right now, with updates often. I know in some of the recent versions Josh has fixed many PTS resets. But with a DD PTS reset, it might get tricky. He hasn't done much work to fix many DD errors if any at all. DD errors are a lot harder to fix than Mpeg errors. But without a PTS reset, I was still able to maintain sync when my DD audio was reported by HeadAC3he to have CRC errors.

Before using BeSweet, rename your audio file to .AC3. Then in BeSweet you could transcode from the DD audio file to .WAV. Then I think TMPGEnc will transcode from .WAV to .MP2 automatically while it muxes.

[TRILIGHT]

I'm just curious... where are you getting streams with Dolby Digital in them that have commercials to be edited out, LiQiCE? The only stuff I record that has DD on it tends to be on premium channels with no commercials.

[LiQiCE]

Originally posted by TRILIGHT
I'm just curious... where are you getting streams with Dolby Digital in them that have commercials to be edited out, LiQiCE? The only stuff I record that has DD on it tends to be on premium channels with no commercials.

I don't think what I'm recording is in Dolby Digital 5.1 ... rather the standard Stereo signal that I'm recording simply is being written in Dolby Digital 2.0 / AC3 (At least I think thats the case, the recording option on the DSR7000 sounds like that, and when I'm pulling the videos with TyTool they play with a Dolby Digital 2.0 384kbps stream)... I thought it'd be easier to record the videos with Dolby Digital 2.0 since thats the final audio stream you want for DVD ... but I didn't realize editing it would be so difficult.

The option on the DSR7000 says something to the effect of Record/Output in Dolby Digital Yes/No.

[TRILIGHT]

I agree, its nice to have Dolby Digital audio but if a channel is not broadcast in DD then a regular MPEG stream is recorded. You say that you're seeing it as 384kbps 2.0 so I don't doubt you (incidentally, where are you reading this information?) but I'm wondering what channel you're getting this from. The only things I've recorded that are in DD are series on Showtime or movies, etc. They run straight through without commercials. I've just not seen a regular channel that is broadcast in DD.

EDIT: I think it just occurred to me what you are doing now. You're creating a multiplexed MPG from within TyTool and you have your TyTool set to change the audio to 384kbps DD. Don't do this. Do not do any transcoding at this point. Go to my website and follow one of the TiVo-to-DVDR guides there. There is one for DVD-Lab and one for DVD Maestro. If your audio is not already Dolby Digital, you'll make it so after all the editing is done and you're creating your DVD.

If in fact the ORIGINAL recording was in Dolby Digital, then you won't have to transcode. But, as I mentioned, there are no commercials to edit out of that material. At least skim through the guides I have on this subject and let me know if you have any questions.

[LiQiCE]

TRILIGHT,

Yeah after further research I realized that you're right, I've been transcoding the audio to Dolby Digital 2.0 384Kbps (I found out this info using PowerDVD XP and right clicking on the video and checking off "Show Information" ... It then tells me what the source of my video and audio is). Anyways ... I unfortunately already deleted a bunch of these recordings off of my TiVo, so I'm stuck with what I've got right now ... thats why I was hoping there was some way to fix it. I used headac3he to create a 192Kbps MP2 and multiplexed that with the video I've got and it makes a video ... TyTool will make a key from it, so I may just end up editing that way unless anyone has a better idea. In the future I'll definitely follow your guide, its too bad I didn't read it before I started extracting some of the videos! Thanks for all your help though.


Originally posted by TRILIGHT
I agree, its nice to have Dolby Digital audio but if a channel is not broadcast in DD then a regular MPEG stream is recorded. You say that you're seeing it as 384kbps 2.0 so I don't doubt you (incidentally, where are you reading this information?) but I'm wondering what channel you're getting this from. The only things I've recorded that are in DD are series on Showtime or movies, etc. They run straight through without commercials. I've just not seen a regular channel that is broadcast in DD.

EDIT: I think it just occurred to me what you are doing now. You're creating a multiplexed MPG from within TyTool and you have your TyTool set to change the audio to 384kbps DD. Don't do this. Do not do any transcoding at this point. Go to my website and follow one of the TiVo-to-DVDR guides there. There is one for DVD-Lab and one for DVD Maestro. If your audio is not already Dolby Digital, you'll make it so after all the editing is done and you're creating your DVD.

If in fact the ORIGINAL recording was in Dolby Digital, then you won't have to transcode. But, as I mentioned, there are no commercials to edit out of that material. At least skim through the guides I have on this subject and let me know if you have any questions.