Dion Galbreath wrote:
> "If i were you id use nut"
> 
> Thanks for your reply. 

Please dont top-post.

> I don't know much about that container. The only
> problem I would think with that would be it probably wouldn't play with
> quicktime, and apple tv and such right? And I would need a dsfilter on
> any system that would want to play the video back in windows media
> player?
> 
> Thanks
> Dion
> 
> 
> 
> 
> 
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of Michael
> Niedermayer
> Sent: Friday, February 22, 2008 12:16 PM
> To: Libav* user questions and discussions
> Subject: Re: [libav-user] mpeg4 format issue
> 
> On Fri, Feb 22, 2008 at 11:14:31AM -0600, Dion Galbreath wrote:
>> We are using ffmpeg for live capture, most formats run perfectly 
>> however, mpeg4, and 3gp formats seem to have a memory leak. Well maybe
> 
>> not a real memory leak, but symptoms exactly none the less... from 
>> what I heard it allocates the index and such for every frame in memory
> 
>> because it conforms to an older mpeg4 spec.
>>
>> ffmpeg's API (av_write_frame(), function which is used to write frame 
>> to file, this function depends on file format. for
>> mov/3gp/3g2/mp4/h264/h263 it is mov_write_packet()this function while 
>> writing frame to disk build file index (stores position of frame on 
>> the disk). this index is required for file header and it shows where 
>> each frame is on the disk. because of early ISO/IEC design decisions 
>> file header SHALL be saved in one piece in any position of file. since
> 
>> we use ffmpeg in 'capture' mode (directshow filter wrapper) it does 
>> not know header size in advance, etc and therefore saves it after 
>> writing ALL frames to disk. So if you are writing 24x7 ffmpeg builds 
>> index for all frames written to disk in memory until you stop writing 
>> then it will flush index. since we don't stop it will run out of 
>> memory at some point.
>>
>>
>> Is there a way to get ffmpeg to output the index to a temp file 
>> instead of memory
> 
> If you have enough swap space your OS will use it and write the index in
> the swap file.
> 
> 
>> or will a newer iso implementation to allow fragmented headers be 
>> used???
> 
> Ive never heard of that, what spec does specify that and where can we
> get that spec (must be free of course).
> 
> Also I would strongly suggest that you use a container which is well
> designed and capable of what you want to do, mp4/mov is not. Any
> container depending on an index will be a bad choice. If i were you id
> use nut, it has a index but it works perfectly fine without the index.
> 
> [...]


-- 
Michel Bardiaux
R&D Director
T +32 [0] 2 790 29 41
F +32 [0] 2 790 29 02
E mailto:[EMAIL PROTECTED]

Mediaxim NV/SA
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