âÒ‘` : [Mp4-tech] About H263 in Mp4 file format

[Dave Singer]

At 12:22  +0800 24/01/07, changfeng niu wrote:
>Hi Dave
>thanks.
>Becuase i want unicast the h263+ stream through Darwin stream server,
>only the stream in  mp4 file format can be supported by Darwin server.
>So i modify Mpeg4Creator to support H263+, I have got it. However, I
>am not sure how to define timestamp in mpe4 file for h263+ by ms or
>frequency. In mp4creator, The defination of timestamp is different
>between H263 and Mpeg4(H264). H263 use miliseconds and Mpeg4 use
>frequence. I don't know why to do so.

I am not familiar with the APIs of mpeg4creator, but timestamps in 
MP4 files are simply numbers on a clock that ticks a given number of 
times per second (the timescale).  There is no theoretical difference 
between MPEG-4 and H.263.
>
>2007/1/17, Dave Singer <singer apple.com>:
>>At 11:30  +0000 17/01/07, Dave Singer wrote:
>>>At 11:36  +0800 17/01/07, changfeng niu wrote:
>>>>Hi everyone
>>>>Do anyone know the definition of H263 in mp4 file format or some
>>>>document including these definition?
>>>>thank you very much  in advance.
>>>>Nathan.niu
>>>>
>>>>______________
>>>
>>>Defined in 3GPP 26.244, the 3GPP file format, available free from
>>>www.3gpp.org.
>>>
>>>(Technically there is a 'short header' mode of MPEG-4 part 2 which
>>>is technically identical to H.263, but no-one uses it).
>>
>>I should have said "no-one (as far as I know) uses MP4 files with
>>MPEG-4 video code-points but using short header MPEG-4 video as a way
>>of exchanging H.263 video".  I didn't mean to imply that no-one
>>worldwide uses mpeg-4 short headers (I do not have universal
>>knowledge, of course).
>>--
>>David Singer
>>Apple Computer/QuickTime
>>
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-- 
David Singer
Apple Computer/QuickTime