This allows one complex filtergraph's output to be sent as input to
another one, which is useful in certain situations (one is described in
the docs).
Chaining filtergraphs was already effectively possible by using a
wrapped_avframe encoder connected to a loopback decoder, but it is ugly,
non-obvious and inefficient.
The decision whether -apad actually does anything is made based on muxer
properties, and so more properly belongs there. Filtering code only
receives the result.
Instead pass the encoder through a newly-added output options struct,
analogous to previously added input options.
Will allow decoupling filtering from encoding in future commits.
There are lots of files that don't need it: The number of object
files that actually need it went down from 2011 to 884 here.
Keep it for external users in order to not cause breakages.
Also improve the other headers a bit while just at it.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
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
The first of these binds inputs of complex filtergraphs to demuxer
streams (with a misleading comment claiming it *creates* complex
filtergraphs).
The second ensures that all filtergraph outputs are connected to an
encoder.
Merge them into a single function, which simplifies the ffmpeg_filter
API, is shorter, and will also be useful in following commits.
Also, rename misleadingly-named init_input_filter() to
fg_complex_bind_input().
Treat it analogously to stream parameters like format/dimensions/etc.
This is functionally different from previous code in 2 ways:
* for non-CFR video, the frame timebase (set by the decoder) is used
rather than the demuxer timebase
* for sub2video, AV_TIME_BASE_Q is used, which is hardcoded by the
subtitle decoding API
These changes should avoid unnecessary and potentially lossy timestamp
conversions from decoder timebase into the demuxer one.
Changes the timebases used in sub2video tests.
Apparently it can happen that avfilter_graph_request_oldest() returns
EAGAIN, yet av_buffersrc_get_nb_failed_requests() returns 0 for every
input.
Works around #10795, though the root issue is most likely in the
scale2ref filter.
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.
Andreas Rheinhardt
Anton Khirnov
James Almer
Niklas Haas