On 3/15/2011 1:40 PM, Eliot Blennerhassett wrote:
On 16/03/11 07:31, Patrick Lai wrote:
Hi,
Is there a precedent for playback/capture compressed audio stream
through ALSA playback/capture interface if underlying hardware supports
decoder + sink& encoder + source capabilities?
No. (Apart from AC3 passthrough to spdif output)
I presume you are referring to IEC958 format. Are there ASoC drivers
that support IEC958 format already? Why is AC3 passthrough acceptable
but not other compressed audio format?
ALSA might be extended to cope with compressed audio with fixed frame
size and bitrate,
but dealing with any VBR encoding is likely to be even
more problematic.
This is because alsa assumes a fixed relationship between samplerate and
data rate, and also assumes that samples fit in an integer number of bytes.
AFAIK dealing with hardware enc/dec has been done using gstreamer plugins.
E.g. http://www.lca2010.org.nz/slides/50315.pdf
Given that audioscience makes cards that support mp3 encode/decode as
well as pcm, I'd like it if alsa *did* support compressed audio...
Which source file can I find an example?
Thanks
Patrick
regards
--
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
--
To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
