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| waveking |
| Posted: Feb 21 2003, 06:21 AM |
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My tv captured mpeg1 files have somehow got all messed up by the recording software.
I think it has messup the framerate. TV transmission in my country is PAL, but the recorded mpeg shows a 29.970 fps. This would have been OK, BUT an audio sync problem has been introduced.
If i open the video in virtualdub and set framerate to 25.000, the audio syns perfectly.
I think i read that mpeg framerate change is not possible without reencoding it...but that is out of question as i would have extremely poor quality....can i somehow demux the audio and mux it back s that it matches with the 29.970 fps video? |
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| ChristianHJW |
| Posted: Feb 21 2003, 04:11 PM |
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Advanced Member
Group: Moderators
Posts: 1768
Member No.: 2
Joined: 7-July 02
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Hmmm ... seems as if the capturing tool messes up the headers of the MPEG files its creating .. you needed a MPEG container editing tool, similar to what Virtualdub is to AVI .... did you try to demux the video stream from the MPEG file using TMPEGencoders 'MPEG tools' ( in the 'file' menue ), and then remuxed it with the audio ?
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| fccHandler |
| Posted: Feb 21 2003, 07:11 PM |
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Administrator n00b
Group: Moderators
Posts: 3961
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Joined: 13-September 02
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The MPEG frame rate is just a 4-bit field in the headers. A long time ago I wrote a crude Visual Basic program that allows you to change the frame rate and aspect ratio of an MPEG (by overwriting the relevant bits). Unfortunately, my upload server isn't working at the moment. If you send me a PM with your e-mail address I can mail it to you (15K zipped).
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May the FOURCC be with you... |
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| waveking |
| Posted: Feb 21 2003, 08:17 PM |
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PMed fcchandler
ChristianHJW...what i did as of now to get around the prob was...open the video in virtualdub...applied my filters(resize,delogo)...set framerate to 25.005 (this synced my video/audio)...applied audio compression and frameserved to TMPGenc. |
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| fccHandler |
| Posted: Feb 22 2003, 03:38 AM |
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Administrator n00b
Group: Moderators
Posts: 3961
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@waveking:
I sent you the program (I think).
Let me know if you got it, because now my e-mail is down too. 
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May the FOURCC be with you... |
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| waveking |
| Posted: Feb 22 2003, 07:15 AM |
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yeah got the app..thanks.
BUT, i opened my mpeg in your app. The app said the framerate was 29.97...virtual dub had said that the framerate should be 25.002....so i asked your app to set the framerate to 25. This caused two effects:
1) WMP failed to load the video!
2) Virtualdub loaded the vide, didnt show any video stream erros, but the video speed fastened as i fast forward and the sync erro was still there  |
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| waveking |
 Posted: Feb 22 2003, 07:18 AM |
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ChristianHJW,
I did try to use the TMPGenc mpeg tools to multiplex the audio/video from the aource into a new "mpeg1 vcd" stream..
but on completion TMPGenc says "147227 s packets cause buffer underflow. The MPEG file might cause error when it played".
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| fccHandler |
| Posted: Feb 22 2003, 08:02 AM |
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Administrator n00b
Group: Moderators
Posts: 3961
Member No.: 280
Joined: 13-September 02
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Damn.
OK, here's my final suggestion:
Use TMPGEnc to demux the video and audio. Use my program to change the frame rate of the demuxed video stream to 25 fps. Then use TMPGEnc to multiplex the new video stream with the original audio stream, and choose Type = "MPEG-1 System (automatic)."
If that doesn't work, then sorry I give up.
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May the FOURCC be with you... |
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| waveking |
| Posted: Feb 22 2003, 11:46 AM |
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OK ill try that and report back.
One query..what's the use of selecting 'MPEG-1 System (automatic)' over VCD one?
BTW, the video is 320x240 resolution  |
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| waveking |
| Posted: Feb 22 2003, 04:46 PM |
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fcchandler....there has been a developement.
infact your app seems to be working.....the problem earlier was that becuase i had forgotted to plug in my brain (then placed in the refrigerator) i was somehow setting the framerate of the movie to 50 fps..instead of 25
perhaps becuase it was so conviniently placed under 29.97
The movie seems to be working now..ill report back if all goes well.
Again sorry for the goof up
[hides in embarrassment]  |
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| fccHandler |
| Posted: Feb 22 2003, 05:44 PM |
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Administrator n00b
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| QUOTE (waveking @ Feb 22 2003, 07:46 AM) | One query..what's the use of selecting 'MPEG-1 System (automatic)' over VCD one?
BTW, the video is 320x240 resolution |
Why select Type = VCD if you're not making a VCD? But if you do intend to make VCDs, you need to record at 352 x 288 (PAL VCD resolution).
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May the FOURCC be with you... |
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