[x264-devel] Bug in mp4 header ?

[TW]

Hi, 

I convert movies using MeGUI for a long time. I convert different type of
sources to 1280 x 720 mp4 which I can use on iPad, iPhone and PS3. I found
out, that the Quicktime player for Windows is a good test vehicle for
verifying the converted movies. If it works on Quicktime player it works
also at PS3 and the other devices.

If the source is a movie with a frame rate of 23.976 fps the converted mp4
always causes an error -2002 on Quicktime player and I get also an error on
PS3.

I did a little bit of research and found out, that the mp4 header of the
movie has wrong entries in the Media Handler Header (mdhd). The attachment
shows two examples. For my opinion the values for stts.sampCnt and
stts.sampDur were defined improper, so that product of these two values
exceeds the allowed range of 32 bit in the mdhd structure. 

It can be shown, that any part of a movie with 23,976 fps, which must not be
longer than 28 min, has correct entries in the header and can be played
without problems. If the part is longer than 28 min the error occurs.

 

(MeGUI 0.3.5.0 with x264 r1649)

Please inform me, if you need some more information.

 

Best regards 

Thomas

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