Paul Braman wrote:
> S/PDIF data is being captured by a Wolfson WM8804 S/PDIF Digital
> Interface Transceiver (or similar) and streamed over USB by a Texas
> Instruments TAS1020B USB Streaming Controller. There are more
> complicated issues regarding exactly what data is transmitted
The WM8804 tra
Clemens Ladish wrote:
>
> Almost all sound cards decode the S/PDIF stream; what you get are
> plain samples (or compressed data pretending to be samples in case
> of AC-3 or DTS). The information in the other bits is usually
> available with the control "IEC958 Capture Default".
Hrmmm ... well, t
Paul Braman wrote:
> Data is broken up on an S/PDIF stream into 64-bit frames grouped into
> 192-frame blocks (1536-byte blocks). Assuming I can properly decode
> all of the status bits in each frame, blah blah blah, I can end up
> with either a PCM stream or, let's say, a compressed-audio stream
>
James Le Cuirot wrote:
>
> "Since compressed data is transmitted in place of PCM data, the bitrate
> of the compressed stream must exactly match uncompressed stereo 16-bit
> PCM bitrate. As a rule, compressed stream (even a multi-channel one)
> having a lower bitrate, compressed stream must be padd
On Mon, 25 Oct 2010 10:45:10 -0400
Paul Braman wrote:
> Interesting, but I see a couple of idiological problems with this
> approach.
>
> "dat" implies reading 32-bit frames at a rate of 48KHz. That's all
> fine and good but an S/PDIF bitstream is going to be pumping data
> faster than that rate
James Le Cuirot wrote:
>
> If you want to try it for yourself, it's as simple as...
>
> arecord -Dspdif -f dat -t raw | spdifextract | ac3dec -6
Interesting, but I see a couple of idiological problems with this approach.
"dat" implies reading 32-bit frames at a rate of 48KHz. That's all
fine and
On Mon, 25 Oct 2010 15:18:03 +0100
James Le Cuirot wrote:
> Apparently a PLL is needed to synchronise the clock frequency but I
> haven't been able to determine whether any sound cards out there have
> these at all. I've heard of some Creative cards having on-board AC3
> decoders but I think this
On Mon, 25 Oct 2010 09:50:19 -0400
Paul Braman wrote:
> I'll assume I want to read in blocks of 1536 bytes-at-a-time as long
> as ALSA is properly synchronizing to the S/PDIF frame and giving me
> aligned blocks. Is this an assumption I can make?
Probably not. I recently thought I would be cleve
Let me first describe the concepts I understand and then I might be
able to ask some questions that make sense.
Data is broken up on an S/PDIF stream into 64-bit frames grouped into
192-frame blocks (1536-byte blocks). Assuming I can properly decode
all of the status bits in each frame, blah blah
