Video from camera: more video than should be, audio is ok

[AnTz0r]

A friend of mine recently made a trip to Syria and shot some videos with her Canon digital photo camera. 2 are supposed to last for 14 seconds, and another one for 29 seconds. When she plays them they are as they should be. However, when I play them, the audio stops after the right amount of time, but the video lasts about twice as long. Hidden scenes!

My guess it's a codec thing that explains the difference between when she plays it back, and when I play back, but it doesn't explain why the extra footage is there in the first place. Besides, she would like to see (and show to others) the extra scenes too.

Is there anybody who can explain this, or who can tell me how I can edit the video so that it will display all the captured frames, indifferent to the codec?

If any of you need access to the video, it's a 50 MB download from http://www.xs4all.nl/~pluympot/private/phaedra/

[Baldrick]

You could try play with vlc media player, it has it own codecs, and see if you notice any different playback.

what video and audio codec are used in the video? identify with avi2clipboard or gspot or mediainfo. You could reencode to another format that is good for sharing on the net like divx,xvid (dr.divx or autogk) or wmv (windows media encoder,windows movie maker).

[AnTz0r]

yes, in VLC it stops at the right moment... 14 seconds

here is a GSpot screenshot:





note that Frames/FrameRate=14.5, the right amount of seconds... or wrong. There is at least 27 seconds of video in the file.

Using DrDivx to encode to DivX lost the extra frames,so did Movie Maker.

AGK gave an error (source format not acceptable or something like that, error -2).

None of them reads the extra frames... damn!

[jagabo]

On my system, both audio and video from Petra_rotated.avi lasted for 27 seconds. Both audio and video in Petra2.avi lasted 42 seconds. I tried Windows Media Player, Media Player Classic, and VideoLAN. All were pretty jerky.

I converted to Xvid/MP3 with VirtualDubMod. Playback was smooth and both audio and video durations were the same.

[AnTz0r]

now THAT is weird... what codec do you have installed, or am i asking a stupid question?

VirtualDubMod can't open those 2 files on my system - VirtualDub cannot decode 4:2:2 Motion JPEG frames with image width or heights that are not a multiple of 16. But I tried using it to convert the unrotated videos, and it didnt recode the "extra" frames.

petra_rotated video lasts for almost a minute here...

[jagabo]

The MJPEG video is being decompressed by Microsoft's "MJPEG Decompressor", quartz.dll, part of DirectShow.

I tried the videos on a faster computer and the originals played smoothly using the same codec.

[AnTz0r]

ok i found the problem... my MPC and WMP plays the video two times slower than it's supposed to... suddenly my friend could swim a lot faster when i tried VNC haha. im such an idiot, why didnt i think of this before...