[FFmpeg-devel] [PATCH] oggpagesize option added

Michael Niedermayer michaelni
Sat Jan 29 18:10:22 CET 2011

On Thu, Jan 27, 2011 at 03:33:27PM -0800, Baptiste Coudurier wrote:
> Hi Gregory,
> On 01/26/2011 01:11 PM, Gregory Maxwell wrote:
>> I think this is a pretty poor solution for the stated problem. It
>> would basically be copying the braindead behaviour we're stuck with in
>> libogg because of some poorly thought out parts of our ABI.
>> The fundamental issue here is that more tightly packed pages mean
>> greater efficiency, but they also mean higher delay. If you don't care
>> about delay? pack away. But if you care then you have issues.
>> The reason this solution is not good is that a straight size limit
>> does _not_ bound the delay very tightly. If the packets being emitted
>> by the codec are very small then you can still get up to 255 of them
>> in a single page? which is the same worst case delay you had with
>> maximum size pages!   This means that your delay bounded streaming app
>> will mostly work, but if the bitrate drops down it will stall and
>> rebuffer.
>> The _correct_ behaviour is to decide how much delay you are willing to
>> tolerate and flush at least that often? regardless of how much data is
>> in the pages.   Gstreamer does this.  Ffmpeg2theora also has a cap on
>> the number of packets it will attempt to place per page.
> I definitely agree with this and implemented something like this in the  
> past.
> Anyway with the per muxer options, it's easy to add.

Does this not apply to several muxers? and is not the existing max_delay
option useable for it?

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The bravest are surely those who have the clearest vision
of what is before them, glory and danger alike, and yet
notwithstanding go out to meet it. -- Thucydides
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