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View Full Version : Help! Strange video length problem!


compusic
6th December 2007, 07:26
I just discover a very strange video length problem.

The only player which can play back m2v file on my system is media player classic. but MPC shows the video's length incorecctly. for a 11 seconds video, MPC shows that it's only 9 seconds. and after MPC plays to the 9 seconds point, though the time counter in MPC stops (stops at 9 seconds), MPC will keep playing to the real end of 11 seconds. then I multiplex the m2v with a audio file to get a mpg file, now MPC shows the length of the mpg file correctly, that's 11 seconds, and playback the mpg file without any problem.

I use gspot to check both files, m2v and mpg, both have the same number of frames.

the m2v makes a big problem for me since I will import it to a music production software to produce bgm and sfx.
in the music software, the m2v file has the length property of 9 seconds, this video clip on the video track can't be longer than 9 seconds. and the whole content ( 11 seconds' content) of the m2v file will be played back in 9 seconds. but if I scrub on the timeline, the video will stop at the 9 seconds point, and the last 2 seconds can't be displayed. Don't doubt my project settings please, I'm sure the project and the m2v file have the same frame rate. btw, in the music software, I should choose the directshow video engine for video display, if choose directx video engine, the video monitor window is black. I don't know which engine MPC uses to display video.

I have import the m2v file into Premiere, the length property and playback have no problem.

I use as many methods as possible to get a m2v file, such as output by Premiere, by Final Cut Pro, multiplex then demultiplex. It seems that as far as it is a m2v file, the length problem does exist. and if it's a mpg file, the problem is gone.

buzzqw
6th December 2007, 08:04
something is missing (Sequence End Codes) ...

run ReStream on m2v file

BHH

compusic
6th December 2007, 09:55
thanks for reply.

but ReStream can't solve this problem. I have tried every possible setting.

buzzqw
6th December 2007, 13:15
could you post the sample ?

BHH

compusic
7th December 2007, 10:44
could you post the sample ?

BHH

thanks. since the attachment here has size limit. I upload to other place. please download from this link:
http://www.sharebigfile.com/en/file/1307/test-zip.html

buzzqw
7th December 2007, 14:21
here mpc report 11 sec...

http://img512.imageshack.us/img512/4496/clipboard01pq8.png (the balck screen is just a overlay issue)

make sure you have the right mpeg2 decoder

just for reference

http://img139.imageshack.us/img139/3893/clipboard01vz8.th.png (http://img139.imageshack.us/my.php?image=clipboard01vz8.png)

BHH

compusic
8th December 2007, 10:56
thanks for reply.

I just make settings like you. but the problem still exists.:(

buzzqw
8th December 2007, 11:13
another try

http://img472.imageshack.us/img472/8900/clipboard01ak5.png

post your graphedit :)

BHH

compusic
10th December 2007, 02:21
What You have drawn is the video decoding flowchart?

that's the difficult job for me, since I'm not good at that, I mean how a video file is decoded. I can see that there're a few MPEG splitter in my system. and I don't know which one is used for the m2v decoding.

buzzqw
10th December 2007, 08:10
download graphedit (on doom9 download section)

launch it
drag&drop your m2v

post it

BHH

reallygreatidea
10th December 2007, 20:09
Yeah, that's weird. Something is definitely missing.

compusic
11th December 2007, 07:02
I have installed the k-lite codec pack version 3.57f.
this one is the first try:
http://img89.imageshack.us/img89/2758/test357fmg6.png

I see that there's a cyberlink video decoder, then I disable that codec in the codec tweak tool, and take a 2nd snapshot:
http://img84.imageshack.us/img84/3169/test358fbetatm7.png

It's different now, but the length problem still exists.

then I unstall k-lite codec 3.57f and install the latest version 3.58fbeta, the snapshot is just the same as the 2nd image. and the same length problem. in fact, I have also tried the older version 3.30, but the same problem.

maybe the cause is due to the mpeg-2 splitter? since that's the only difference between our snapshots.

mpucoder
11th December 2007, 17:28
I finally had time to look at this. MuxMan has an internal analyzer (but the release version does not display details, it's for debug purposes). Here's what the final group of pictures looks like.
Sequence at 80C208, 544 fields.
Extension at 80C254, 544 fields.
Extension at 80C25E, 544 fields.
GOP at 80C26A, 544 fields.
Picture at 80C272, 544 fields.
Extension at 80C27A, 546 fields.
Picture at 824AD8, 546 fields.
Extension at 824AE1, 548 fields.
Picture at 8302DB, 548 fields.
Extension at 8302E4, 550 fields.
Picture at 831508, 550 fields.
Extension at 831511, 552 fields.
Picture at 832DA0, 552 fields.
Extension at 832DA9, 554 fields.
Picture at 84172E, 554 fields.
Extension at 841737, 556 fields.
Picture at 84359B, 556 fields.
Extension at 8435A4, 558 fields.
Picture at 844E0B, 558 fields.
Extension at 844E14, 560 fields.
Seq_end at 84C11C, 560 fields.
USER at 84C120, 560 fields.
What is unusual is after the sequence_end header there is user data. This is what is confusing the programs (including MuxMan which multiplexed the user data as a still of 10 frames). Remove it with a hex editor and everything should be OK.
edit - btw the user data appears to be an index, the last 4 bytes are "INDX" in ascii

compusic
13th December 2007, 03:00
I finally had time to look at this. MuxMan has an internal analyzer (but the release version does not display details, it's for debug purposes). Here's what the final group of pictures looks like.



thanks. but that's too difficult for me.

and I have tested the m2v file on different pcs. It's strange that some have the problem while some don't have.

maybe it's still due to a unknown problem of decoder.