This is only a preparatory step to a fully threaded architecture and
does not yet make decoding truly parallel - the main thread will
currently submit a packet and wait until it has been fully processed by
the decoding thread before moving on. Decoder behavior as observed by
the rest of the program should remain unchanged. That will change in
future commits after encoders and filters are moved to threads and a
thread-aware scheduler is added.
It is only used for flushing the subtitle decoder, so allocate a
dedicated packet for that.
Keep Decoder.pkt unused for now, it will be repurposed in future
commits.
Make the function process just one input stream at a time and save an
indentation level. Also rename it to ist_add() to be consistent with an
analogous function in ffmpeg_mux_init.
Currently of_output_packet() reuses the input packet, which requires its
callers to submit blank packets even on EOF, which makes the code more
complex.
It is set by the muxing code, which will not be synchronized with
encoding code after upcoming threading changes. Use an encoder-private
variable instead.
Packets submitted to the muxer now have their timebase attached to them,
so the muxer can do conversion to muxing timebase and avoid exposing it
to callers.
There is no reason to postpone it until opening the encoder. Also, abort
when the input stream is unknown, rather than disregard an explicit
request from the user.
The code will currently add a small offset to avoid exact midpoints, but
this can cause inexact results when a float timestamp is exactly
representable as an integer.
Fixes off-by-one in the first frame duration in multiple FATE tests.
Current code marks the output stream as finished and waits for a flush
packet, but that is both unnecessary and suspect, as in theory nothing
should be sent to a finished stream - not even flush packets.
Make all relevant state per-filtergraph input, rather than per-input
stream. Refactor the code to make it work and avoid leaking memory when
a single subtitle stream is sent to multiple filters.
Set them in ifilter_parameters_from_dec(), similarly to audio/video
streams. This reduces the extent to which sub2video filters need to be
treated specially.
This function should not take an InputStream, as it only uses it to get
the InputFile and the timebase. Pass those directly instead and avoid
confusion over dealing with multiple InputStreams.
This queue should be associated with a specific filtergraph input - if
a subtitle stream is sent to multiple filters then each should have its
own queue.
This code is a sub2video analogue of ifilter_send_frame(), so it
properly belongs to the filtering code.
Note that using sub2video with more than one target for a given input
subtitle stream is currently broken and this commit does not change
that. It will be addressed in following commits.
When the filtergraph has no inputs, it can be configured immediately
when all its outputs are bound to output streams. This will simplify
treating some corner cases.
Anton Khirnov