[x264-devel] Appending an iFrame to the start of a h264 video?

[Tomas Carnecky]

Make sure ffmpeg is producing raw .264 files (with no headers or such). 
A simple check is to see if the first three of four bytes of the file 
are (0x00) 0x00 0x00 0x01.

tom

Cary Fitzhugh wrote:
> Thanks for the reply!
> 
> I'll keep looking if you all think it is possible.
> I may be getting tripped up by ffmpeg adding some header information onto the front. I'm not sure.
> 
> At least I have a clue that it may be possible.
> 
> Thanks so much,
> Cary
> 
> Alex Giladi wrote:
>> "cat movie1.264 movie2.264 > longer_movie.264 " should suffice, AFAIK.
>>
>> On Wed, Jul 9, 2008 at 12:41 PM, Cary Fitzhugh <cfitzhugh at echo360.com> wrote:
>>> Hello --
>>>
>>> I'm trying to figure out if there is a way to concatenate two h264 files without reencoding.
>>>
>>> I am making edits of longer h264 videos.
>>> In order to make sure that my video starts on an iFrame - I want to use ffmpeg to encode a single frame at the start
>>> time.  Then in a subsequent call - do a -vcodec copy on the rest of the edit.
>>>
>>> This provides me with 2 h264 movies.  One is 1 frame long and is an iframe.  The second movie is the rest of the edit.
>>>
>>> I do not understand the h264 codec well enough - which is why I'm writing you all.  It makes sense in my head, that if I
>>> were to just concatenate the raw h264 files together and wrap it I should have a valid h264 file.
>>>
>>> In my movies I do not have B frames, just P and I frames.  My understanding is that P frames are only moving forward.
>>> So prepending that initial i frame onto the front of the edit should work fine.
>>>
>>> I tried this, and when I combined the two it got very swirly and messed up on vlc.
>>>
>>> ANy ideas if this is possible?  I would really like to do this no matter how convoluted I need to get.  When I'm editing
>>> 1 - 4 hour movies all the time I would rather not wait 20% of real time to make an edit - just for that first iframe.
>>>
>>> Thanks for any insight into this.
>>>
>>> Cary FitzHugh
>>> _______________________________________________
>>> x264-devel mailing list
>>> x264-devel at videolan.org
>>> http://mailman.videolan.org/listinfo/x264-devel
>>>
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