And clean up any old pending headers if we receive a new identification
header, or if we receive a new set of headers via caps.
Otherwise it might happen that we receive one or more header but not
all, and then afterwards all headers again, and libvorbis does not like
getting headers passed multiple times and would error out.
It only makes sense to pass the very latest headers to the decoder at
the time we can actually make use of them.
https://bugzilla.gnome.org/show_bug.cgi?id=796980
If new headers arrive after we are initialized, we need to make
sure that they are indeed valid.
A vorbis bitstream always begins with three header packets and must
be in order.
Also some streams have unframed (invalid?) headers that might
confuse and disrupt the decoding process.
Therefore if ever we see new headers, we accumulate them and once
we get a non-header packet we check them to make sure that:
* We have at least 3 headers
* They are the expected ones (identification, comments and setup)
* They are in order
* Any other "header" is ignored
If those conditions are met, we reset and reconfigure the decoder
https://bugzilla.gnome.org/show_bug.cgi?id=784530
This is a followup commit to b95725c37e
* Resetting the decoder should only happen when we get a new initialization
header (0x01) and not on the other headers
* The initialized variable only gets set to TRUE once all headers have
been parsed. Also check if the vorbis_info struct has been properly resetted
also. Failure to do that would cause vorbisdec to error if it got
two initialization header in a row (the first would configure the underlying
library and the second one would error out because it's already initialized)
https://bugzilla.gnome.org/show_bug.cgi?id=779515
They are very confusing for people, and more often than not
also just not very accurate. Seeing 'last reviewed: 2005' in
your docs is not very confidence-inspiring. Let's just remove
those comments.
For the USE_TREMOLO case, GstVorbisDec doesn't have
a vb member. Besides, Tremolo's vorbis_dsp_synthesis()
expects a vorbis_dsp_state to be passed as first
argument. Not a vorbis_block.
Rework the audio caps similar to the video caps. Remove
width/depth/endianness/signed fields and replace with a simple string
format and media type audio/x-raw.
Create a GstAudioInfo and some helper methods to parse caps.
Remove duplicate code from the ringbuffer and replace with audio info.
Use AudioInfo in the base audio filter class.
Port elements to new API.
