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| LeoGetz |
| Posted: Jan 30 2004, 04:20 PM |
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Advanced Member
Group: Members
Posts: 180
Member No.: 7875
Joined: 20-December 03
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I've recently come across a movie..
Yes I downloaded it and it had bad frames.
The movie however was encoded with DivX 4 (OpenDivX) not DivX 3 Low-Motion.
It had bad frames at 63:35 minutes.
When I opened this movie with AVIPreview.exe the runtime of the movie ended at 63:35.
When I opened the same movie with VirtualDub v1.5.10 build 18160 then did a scan of the video stream for errors, nothing was detected. I played the movie and was able to view the bad frames. Yet no errors were detected by VirtualDub while playing.
I was able to make 2 short clips one with the bad frames and another without (after redownloading the movie and using a Hex Editor to insert the bytes) each being 14sec (428frames) 3 KeyFrames long 1.95M using Direct Stream Copy for the video and audio.
My guess as to the reason why AVIPreview.exe was able to catch these bad frames while VirtualDub does not is because the KeyFrames are in good shape. The frames that follow the KeyFrame in question however are not.
Now I would like to post these 2 clips someplace so others can have a look and perhaps figure out a way to improve virtualdub's ablility to recognize and find the errors while scanning for bad frames.
If anyone knows of a so-called free web site where I can post these 2 clips your help will be greatly appreciated.
Please Post your reply to newwl@netscape.net.
Thanks In Advance.
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| i4004 |
| Posted: Jan 30 2004, 08:02 PM |
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Advanced Member
Group: Members
Posts: 2432
Member No.: 4935
Joined: 24-June 03
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how is vdub responsible for a bad frames produced by lousy codec?
although i don't have the slightest clue what's vdub doing on "scan for errors"(as i didin't had the need to use it...) i believe only thing it should detect are errors in avi container itself;who's vdub to tell what went wrong on compression?
also,your video playes OK,so where's the problem?
vdub si not responsible for codec errors....
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my signature:
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| LeoGetz |
| Posted: Jan 31 2004, 12:21 PM |
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Advanced Member
Group: Members
Posts: 180
Member No.: 7875
Joined: 20-December 03
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| QUOTE (i4004 @ Jan 30 2004, 02:02 PM) | | your video playes OK,so where's the problem? |
No it does not play OK especially if I were to play it with AVIPreview.exe.
The actual runtime of the movie is 87:57 minutes. When the movie stopped at a runtime of only 63:35 that means that I wouldn't get to watch the last 24:22 of this movie But Most Importantly also letting me know that this movie Does Have Errors in its frames.
Maybe and most likely this is a lousy compression. But isn't that what VDub is suppose to detect when you use 'Scan Video Stream for Errors'?
If not what is the purpose of 'Scan Video Stream for Errrors'? Just to make sure the keyframe are ok... thats B.S.
The only reason I'm mentioning any of this is because there are some movies especially those that are encoded with DivX 3 Low-Motion that do play OK with AVIPreview even though there are frames with 'lousy' compression.
Who whats to watch a movie with sh*t sceens in the middle of it... I sure as h*ll do not. And the only way I get to find this out is when I try to recut the movie.
I did a scan of the video stream with VDub prior because it's alot quicker than playing the movie (Dub in Progress) and nothing was detected. Yet when I go to recut the movie with another or same codec... OH NO... ERRRors....B.S...
So at least now, I was able to grab like I said 2 clips both with 'DSC' for video and audio one that has the B.S frames and one without. Now WHY was it that AVIPreview was able to pick up on this but VirtualDub did not?
If you or the creator of VirtualDub can figure this out then thats one more great advance for VirtualDub in my opinion and one step closer to figuring out why neither program can really detect errors like lousy compression in videos encoded with DivX 3 Low-Motion. |
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| phaeron |
| Posted: Jan 31 2004, 10:40 PM |
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Virtualdub Developer
Group: Administrator
Posts: 7773
Member No.: 61
Joined: 30-July 02
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VirtualDub relies on the video codec to detect and return an error code on a bad frame, because the codec is the only code in the system that knows the compressed format. Period. If the codec doesn't reliably detect bad compressed data, there is nothing I can do.
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| LeoGetz |
| Posted: Feb 1 2004, 11:07 PM |
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Advanced Member
Group: Members
Posts: 180
Member No.: 7875
Joined: 20-December 03
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Thanks phaeron for the reply...
At least now I know a little bit more..
Thanks for the knowledge. |
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