[FFmpeg-devel] [PATCH] Write Pixel Aspect Ratio tag to QuickTime files

[Jean-Daniel Dupas]

Le 8 juil. 2010 ? 04:22, Baptiste Coudurier a ?crit :

> On 07/07/2010 07:12 PM, Daniel Kristjansson wrote:
>> On Wed, 2010-07-07 at 14:35 -0700, Baptiste Coudurier wrote:
>>> On 07/07/2010 02:17 PM, Daniel Kristjansson wrote:
>>>> It's required in the spec, p118 of qtfs.pdf, "Pixel aspect ratio. This
>>>> extension is mandatory for video formats that use non-square pixels."
>>> My specs say MPEG-4 and uncompresed YCbCr. Dated 2007-09-04
>> 
>> Mine is dated 2010-05-03.
> 
> Nice a new one :)
> Unbelievable that they still refuses to document the 'ctts' atom ...

This is the version with the QuickTime meta data format specification (keys/ilst atoms).

http://developer.apple.com/mac/library/documentation/QuickTime/QTFF/RevHistory/QTFFrevision_history.html#//apple_ref/doc/uid/TP40000939-CH228-SW1

FWIW, the ctts atom is fully documented in the MPEG-4 part12 specification [8.6.1.3] (except that they use signed offset despite what the spec says).

aligned(8) class CompositionOffsetBox extends FullBox(?ctts?, version = 0, 0) { 
	unsigned int(32) entry_count;
	for (int i=0; i < entry_count; i++) {
		unsigned int(32) sample_count; 
		unsigned int(32) sample_offset;
	}
}