This change adds two meta-information fields to the processing
queue item structure. Both of them will be used for more
detailed logging and for the human-readable processing
queue description.
There are currently three types of prcessing queue items:
- source (file, alsa, rtp)
- proc (format, codec)
- sink (file, alsa, rtp)
Let's assign corresponding type for each item.
This would facilitate logging and the queue checking.
In some cases it's required to wait for some queue items
to finish processing. For example, the ALSA sink writes the
audio samples to the buffer in non-blocking mode, so as soon
as all of them will be written, a program may finish execution,
causing the playback abort.
To prevent that, this change extends the library's API, allowing
each queue item to have a processing state callback that returns
a positive integer if processing is not finished yet,
and 0 otherwise.
Since this change, the libosmogapk uses the Osmocom logging
framework. By default, logging is disabled and could be enabled
by the external applications calling the osmo_gapk_log_init()
with a desired log target as an argument.
To avoid a naming conflict between libosmogapk and other projects
during linkage, all the exposed symbols should have an unique
prefix. Let's use 'osmo_gapk' for that.
To be able to use the library, external applications need to know,
which symbols are exposed. This information is provided by header
files, which are being installed to a system's ${includedir}
since this change.
On some systems the ALSA output buffer is pretty big, and
if the audio samples are not being passed into the buffer
quickly enough, it becomes starved for data, resulting
in an error called underrun.
Previously, when it happenned, GAPK used to stop processing
with the following message (where X is a random number):
[+] PQ: Adding ALSA output (dev='default', blk_len=320)
[!] pq_execute(): abort, item returned -1
[+] Processed X frames
According to the ALSA documentation, the pcm_handle
changes its state when the problem happens, and should
be recovered using the snd_pcm_prepare() call. This change
actually does that.
Vadim Yanitskiy
Harald Welte