For hardware engineer types re: sound controlers and/or codec chips ??
jwendel10 at comcast.net
Sat Sep 5 20:51:11 UTC 2009
On 09/05/2009 10:36 AM, William Case wrote:
> I am chasing down the creation or production of sound on my computer.
> Everything is fitting into place after being at it, on and off, for a
> couple of years. However, there is one hardware answer I don't seem
> able to chase down.
> Where is the sound data kept immediately on arrival at the sound card?
> Whether analog or digital; whatever the source; sound arrives at the
> sound card or at on-board chip(s). Whether the sound is in 'chunks',
> 'segments' or 'packets', the sound data has to be stored somewhere on
> the sound card, before being coded or decoded, or before being moved to
> the DMA.
> I expect that the memory requirements are small, perhaps only a few
> bytes, but none-the-less, the sound card has to (I would think) store
> the data somewhere before processing it and putting it in a DMA buffer.
> Is my assumption about temporary, perhaps 1-2 ticks, storage accurate?
> Where is this data stored?
> Does the sound card itself have some small capacity for memory?
> -- SRAM or DRAM?
> If so, is this storage a property or function of the sound controller or
> the codec chip?
> Is there a way to tell the size or nature of this memory from the
> specifications, or, the hardware definitions in lshw, or,
> cat /proc/asound/card*/pcm*/info?
> Is, for some reason, this information propitiatory to manufacturers ?
> If it is propitiatory, can you give me a best guess?
> In the end, this is not a terribly important issue, other than without
> an explanation, the understanding of the logic chain for hardware and
> software used by sound is broken.
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