Signed-off-by: Rémi Duraffort <ivoire@videolan.org>

libavcodec seems to do the same and didn't actually found a reaso earlier
patch did what it did. Copying nals helps if you do slices, so it doesn't
do one nal at a time.

(cherry picked from commit d3dd9028)

No functional changes.
(cherry picked from commit bb9c9396)

(cherry picked from commit fb46b4a1)

Use highlevel function snd_pcm_recover() the recover from error states.

Read first before using snd_pcm_wait(), just like arecord does.
(cherry picked from commit 4b0e0dcd)

i_audio_mode should be used for the audio input mode (if ever supported).

Also do not enumerate every tuner two times when one is enough.

The table is not needed. Furthermore, each input is now enumerated
once rather than twice.

Maybe one day we will support autodetecting V4L2 device nodes
(as file://) but until then...

For the time being, mmap() is used if supported, otherwise read() if
supported, otherwise fail. This makes the user pointer method dead
code. It might make sense to revive it on capable device drivers to
support zero copy, but until then that method is no better than mmap().

Also an integer values in the MRL (v4l2://standard=XXX) is now
interpreted as a v4l2_std_id bit field, just like the command line
option (--v4l2-standard=XXX). This fixes an out-of-bound read with
large values.

Keeping the list of video standards in memory was almost pure waste:
The whole data set was only used to print one debug message.

The list of supported standards depends on the selected input.
So listing the standards during probe was wrong in any case.