Re: bttv and saa driver: buffer question

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Hi Franz,

Double buffering is up to u ;). Just get at least 2 Buffers from the driver, 
and use them one after another as a ringbuffer :). U could have more buffers, 
so u don't need to worry, if u need more time to process one picture.

Streaming is done, as long as u pass a buffer back to driver to fill it. No 
Buffer - no Streaming. Buffers are filled with continuing frames, so don't 
expect to dequeue 5 Buffers to get 5 (seperated) pics per second. This would 
produce just a line of 5 Pictures out of 25, not 5 Pictures with 4 Frames 
between them. U have to make the correct timing by urself to do that ;).

Hope i could help u a little bit.

Michael

Am Donnerstag, 26. Juni 2003 11:27 schrieb Franz Reinhardt:
> Hi,
>
> after looking through the code of bttv-0.9.10 and saa7134-0.2.7, I have
> still some questions about streaming and reading the video resource.
>
> If I've understood it correctly, this is how it's done.
>
> Framebuffer   --------------------->  System Memory (cacheable)
> Video-Card     DMA Transfer                   many buffers
>                        (steered by interrupt)
>
> Do the driver use double buffering for the framebuffer to separate the
> frames properly ?
>
> Is streaming done all the time, or does it stop after filling up all the
> enqueued buffers ?
>
> TIA,
>
> Franz
>
>
>
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