These functions used to be passed directly to pthread_create(), which
required them to return void*. This is no longer the case, so they can
return a plain int.
Current callstack looks like this:
* ifilter_bind_ist() (filter) calls ist_filter_add() (demuxer);
* ist_filter_add() opens the decoder, and then calls
dec_add_filter() (decoder);
* dec_add_filter() calls ifilter_parameters_from_dec() (i.e. back into
the filtering code) in order to give post-avcodec_open2() parameters
to the filter.
This is unnecessarily complicated. Pass the parameters as follows
instead:
* dec_init() (which opens the decoder) returns post-avcodec_open2()
parameters to its caller (i.e. the demuxer) in a parameter-only
AVFrame
* the demuxer passes these parameters to the filter in
InputFilterOptions, together with other filter options
Rename dec_open to dec_init(), as it is more descriptive of its new
purpose.
Will be useful in following commits, which will add a new path for
opening decoders.
Do not construct the name manually from input file/stream indices.
This is a step towards avoiding the assumption that filtergraph inputs
are always fed by demuxers.
The computation is based on demuxer properties, so that is the more
appropriate place for it. Filter code just receives the desired
start time/duration.
Previously, the demuxer would register decoder with the scheduler, using
InputStream as opaque, and pass the scheduling index to the decoder.
Now the registration is done by the decoder itself, using DecoderPriv as
opaque, and the scheduling index is returned to demuxer from dec_open().
decoder_thread() then no longer needs to be accessed from outside of
ffmpeg_dec and can be made static.
It is done based on demuxer information, so that is the more appropriate
place for this code.
This is a step towards decoupling Decoder and InputStream.
* as this decision is based on demuxing information, move it from the
decoder to the demuxer
* as the issue being addressed is latency added by frame threading, we
only need to disable frame threading, not all threading
Add it to decoder options instead, to be processed when opening the
decoder. This way it won't be overridden by flags the user might be
setting otherwise.
Currently it requires every single OPT_SPEC option to be accompanied by
an array of alternate names for this option. The vast majority of
options have no alternate names, resulting in a large numbers of
unnecessary single-element arrays that merely contain the option name.
Extend the option parsing API to allow marking options as having
alternate names, or as being the canonical name for some existing
alternatives. Use this new information to avoid the need for
abovementioned unnecessary single-element arrays.
Change the main loop and every component (demuxers, decoders, filters,
encoders, muxers) to use the previously added transcode scheduler. Every
instance of every such component was already running in a separate
thread, but now they can actually run in parallel.
Changes the results of ffmpeg-fix_sub_duration_heartbeat - tested by
JEEB to be more correct and deterministic.
See the comment block at the top of fftools/ffmpeg_sched.h for more
details on what this scheduler is for.
This commit adds the scheduling code itself, along with minimal
integration with the rest of the program:
* allocating and freeing the scheduler
* passing it throughout the call stack in order to register the
individual components (demuxers/decoders/filtergraphs/encoders/muxers)
with the scheduler
The scheduler is not actually used as of this commit, so it should not
result in any change in behavior. That will change in future commits.
Anton Khirnov
Andreas Rheinhardt