In Sync - Out of Sync

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In Sync - Out of Sync

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jamesmcuk

Suspended due to non-functional email address

29. August 2002 @ 08:55

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Hi everyone I would be very greatful if anyone could help me. I am burning an SVCD which completes and all seems well I watched the Mpeg before the burn and it was perfect sync and then I tested it after and still perfect sync of the audio and video. In fact it all seemed rosy until I put it in the DVD and although it played OK the sound was behind the Video. Why would that be? Its fine on the PC! Could it be something to do with too many frames per second and the dvd isn't adjusting for it yet the computer will?

Thanks in Advance!

Oh and does anyone know why in higher than normal motion scenes the picture starts to go blocky.

Thanks

J

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afogh

Suspended due to non-functional email address

30. August 2002 @ 06:50

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Problem 1: A MPEG2 software player has huge amounts of memory available which means it can do read-ahead and decode well in head of time. A hardware player on the other hand is short on memory and reads from the disc when the next blocks should be read, when it should be decoded and when it should be displayed - this allows a smooth playback with minimal memory usage. Now writting these timestamps is part of the so called "mulitplexing" which is often considered the most difficult part of mastering an MPEG2 stream, therefore many encoders will fuck this part up and it'll work great with a software player, but won't with a hardware player. The solution is to multiplex with a good multiplexer.

Problem 2:
MPeg2 works by saving 16x16 pixel blocks of differences between the current picture and the picture before and after. To further reduce the size, it ignores "too many" differences. Therefore when there is a lot of action differences will be ignored and the 16x16 pixel blocks becomes visible. This ofcause is a vast oversimplification of MPeg2, but it is the basic of it. The Mpeg2 standard does not say how you figure out when differences are too big nor the details of how to find these differences - this leaves a great deal of possibillity to write a good or a bad encoder.

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jamesmcuk

Suspended due to non-functional email address

30. August 2002 @ 09:23

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Thanks for the advice its all a bit daunting a first this stuff I guess it takes time. Do you reccomand a good encoder I used TMPGenc?

Thanks

J

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afogh

Suspended due to non-functional email address

2. September 2002 @ 11:43

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Usually TMPegenc is considered to be one of the best encoders.

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Isis1

Newbie

13. September 2002 @ 10:45

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I've just spent 50 hours encoding a file using TMPGEnc. I followed the instructions in the DVD to SVCD guide to the letter. I've made other SVCDs and had no problems until this last one. This was the first time I had to split the mpeg, but once again I used the tools within TMPGEnc.

Yet now, after 50 hours I see the result is worthless. The video is fine... the audio is fine.. The problem is that they are not in sync. Do I delete all this work and start over or does someone have any clever ideas. I still don't understand why after several successful SVCDs, I ended up with this major screw up.

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afterdawn.com > forums > archived forums > mpeg-1 and mpeg-2 encoding (avi to dvd) > in sync - out of sync


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