In article , John
Legon
wrote:
Jim Lesurf wrote:
Hence I'm currently trying to decide if his working on having EZCap
output audio (without some further processing on the computer) is
chasing a boojum. So not an 'alsa' problem at all. But I dunno as I
know zero about the EZCap. My experience is only with the 290e and
FUNcube.

I have the Easycap dongle and a couple of USB tuner sticks and they are
very different devices. The Easycap (or EZCap) is basically a digitizer
which samples an analogue composite video or S-video input, with audio,
and sends PCM data to the USB. I don't know to what extent that data is
compressed, but I do know that it requires a fast USB connection and a
fast processor otherwise it simply won't work.

That may mean the problem is that Davey either can't identify the format
for the audio, or that it has to be processed on the host machine.

ALSA can routinely do things like shuffle between 16bit and 24bit and LE
and BE byte sets. Even resample/convert the sample rate. But not do things
like decode mp3, say. That needs the addition of some other software
process in the chain.

I don't have an EZCap. So can't do any tests. Davey reports the EZCap as
giving alsa device ID numbers and strings. But then says he gets 'empty'
streams (0 values) when using these with arecord. Which indicates something
somewhere isn't set up correctly by him. But I can't tell what the problem
may be from here. :-)

I've had such empty results from another device. But that was IIUC because
the device was being controlled incorrectly. That may also be true here.
The problem there seemed to be a bug in some versions of the HID USB
libraries. I changed library and the code worked. But if that's the problem
his software may need re-compiling and linking against an alternative
library.

Slainte,

Jim

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