AutoGK/xvid synchronization problems w/HDTV transport streams

[carteriii]

I've been using AutoGK to convert HDTV mpeg transport streams (created w/BTV & a Fusion5 Lite card) to xvid (so I could watch them with a MediaMVP), and found that a large percentage (perhaps 50-70%) of the shows result in tremendous audio sync problems. The audio synchronization in the file produced by AutoGK will be perfect up until a particular commercial break, and then the audio will suddenly be out of sync by a minimum of a full second and often 2-3 seconds. The lack of synchronization then remains constant for the rest of the video file.

The problem in the syncrhonization usually starts immediately before or after a commercial break. A few times I have found the original file will demonstrate a hiccup of some sort in that location. For example, in one situation NBC was doing a quick self-promotion for future shows (before returning to the primary show) which was supposed to end with the audio saying, "on N...B...C." The break was cut short such that the audio only contained "on N...B", then the screen quickly went black, and the primary show restarted. While watching this within BTV from the original transport stream, the audio remains synchronized. However, AutoGK always produces 2-second out-of-sync audio after that point.

I do not know whether the hiccup I just described is the result of a problem with the streaming on my computer, or whether I have an accurrate representation of the signal broadcast by NBC. However, this is only one situation in which I found an obvious hiccup. Other times the syncrhonization problem seems to start after a seemingly normal transition between scenes or commercials. Regardless of the cause, BTV is able to play synchronized audio & video for the entire stream, but AutoGK never gets it right. I've tried several different audio formats within AutoGK, but nothing preserves the synchronization beyond that one specific point.

I want to believe that a properly synchronized file can be created by AutoGK since BTV plays the entire transport stream just fine. How is BTV maintaining synchronization from the original file, but AutoGK losing the synchronization? Does anyone know AutoGK well enough, or the more complete tools & utilities used by AutoGK, in order to suggest something that can be done? Has anyone else experienced this problem? I realize the number of HDTV and AutoGK users is probably pretty small, but I'm hopeful that one of you with greater audio/video knowledge can help me out. I'd love for Snapstream to simply offer up a supported version of ShowSqueeze for HDTV, but until that happens I'd like AutoGK to retain audio synchronization more frequently.

[Jkramer5]

I edit HDTV .ts files with video redo, compress them to xvid with auto gk and get no sync issues, don't know that I'm doing anything special, just wanted to let you know that what you're trying is totally possible.

It may be that whatever your editing the commercials out with is causing the issue.

[carteriii]

It may be that whatever your editing the commercials out with is causing the issue.

I'm actually not editing out the commercials at all. I'm running directly on the original file as created by the Fusion5 card, but your message does give me hope. Thanks.

[carteriii]

After having a bit more time to witness the problem and start to see a trend, I've noticed that this problem happens almost exclusively with shows on NBC. HDTV streams on other networks are generally fine. There is something in how NBC cuts to & from commercials that causes AutoGK to consistently produce synchronization problems. I've recorded non-HD versions of the same shows and the commercial cuts do appear to be the same, so I don't believe the problem is in the capture on my computer. I (at least currently) believe there is something in the NBC signal that causes the problems for AutoGK. If I'm really the only one seeing this, then perhaps it's the result of something my local NBC affiliate (in Austin, TX) is doing to insert their commercials. If anyone else lives in this area and does not have the problem, please let me know.

I suspect I need to head over to the AutoGK/Doom9 forums to get some additional help, but please let me know if you are reading this have greater lower-level knowledge of all this. I don't have any synchronization problems when watching the original stream, so I'm still hopeful that something can be done to produce proper synchronization by AutoGK.

[gohandbz8]

Although this might not help your problem directly, it might be a option. When I use VideoRedo to edit out the commercials, the software actually fixes audio/video sync issues and shows a log of it after all is said and done. After cutting out the commercial, I then use AutoGK to convert to Divx (haven't tried converting to xvid yet) and haven't seen any sync issues at all. I do record E-Ring on NBC every week in HD and its works fine in divx.

[mv-clear]

not sure but i think what u are seeing is not a result of the commercials but a problem with bad data in the tp stream. the videoredo removes these frames and resyncs the audio. if the tp stream has bad data i.e a hiccup in the file it could be the problem. if it only occurs on one station it sounds like the signal is weaker on that station. just my thoughts. i will also be trying to convert my tp streams to divx but dont currently have the pc horsepower.
mv