Unlike other cases where the closed captions are embedded in the
video stream as MPEG-2 userdata or H.264 SEI data, with MOV files
the captions are often found on a separate "e608" subtitle track.

Add support for playout of such files, leveraging the new ccfifo
mechanism to ensure that they are embedded into VANC at the correct
rate (since e608 packets often contain batches of multiple 608 pairs).

Note this patch includes a new file named libavdevice/ccfifo.c, which
allows the ccfifo functionality in libavfilter to be reused even if
doing shared builds.  This is the same approach used for log2_tab.c.
Signed-off-by: Devin Heitmueller <dheitmueller@ltnglobal.com>
Signed-off-by: Limin Wang <lance.lmwang@gmail.com>

THis filter can correct certain issues seen from upstream sources
where the cc_count is not properly set or the CEA-608 tuples are
not at the start of the payload as expected.

Make use of the ccfifo to extract and immediately repack the CEA-708
side data, thereby removing any extra padding and ensuring the 608
tuples are at the front of the payload.
Signed-off-by: Devin Heitmueller <dheitmueller@ltnglobal.com>
Signed-off-by: Limin Wang <lance.lmwang@gmail.com>

Because the interlacing filter halves the effective framerate, we
need to ensure that no CEA-708 data is lost as frames are merged.

Make use of the new ccfifo mechanism to ensure that caption data
is properly preserved as frames pass through the filter.

Thanks to Thomas Mundt for review and noticing a couple of
missed codepaths for injection on output.  Thanks to Lance Wang
for pointing out a memory leak.
Signed-off-by: Devin Heitmueller <dheitmueller@ltnglobal.com>
Signed-off-by: Limin Wang <lance.lmwang@gmail.com>

Various deinterlacing modes have the effect of doubling the
framerate, and we need to ensure that the caption data isn't
duplicated (or else you get double captions on-screen).

Use the new ccfifo mechanism for yadif (and yadif_cuda and bwdif
since they use the same yadif core) so that CEA-708 data is
properly preserved through this filter.
Signed-off-by: Devin Heitmueller <dheitmueller@ltnglobal.com>
Signed-off-by: Limin Wang <lance.lmwang@gmail.com>

The existing implementation made an attempt to remove duplicate
captions if increasing the framerate, but made no attempt to
handle reducing the framerate, nor did it rewrite the caption
payloads to have the appropriate cc_count (e.g. the cc_count needs
to change from 20 to 10 when going from 1080i59 to 720p59 and
vice-versa).

Make use of the new ccfifo mechanism to ensure that caption data
is properly preserved.
Signed-off-by: Devin Heitmueller <dheitmueller@ltnglobal.com>
Signed-off-by: Limin Wang <lance.lmwang@gmail.com>

When transcoding video that contains 708 closed captions, the
caption data is tied to the frames as side data.  Simply dropping
or adding frames to change the framerate will result in loss of
data, so the caption data needs to be preserved and reformatted.

For example, without this patch converting 720p59 to 1080i59
would result in loss of 50% of the caption bytes, resulting in
garbled 608 captions and 708 probably wouldn't render at all.
Further, the frames that are there will have an illegal
cc_count for the target framerate, so some decoders may ignore
the packets entirely.

Extract the 608 and 708 tuples and insert them onto queues.  Then
after dropping/adding frames, re-write the tuples back into the
resulting frames at the appropriate rate given the target
framerate.  This includes both having the correct cc_count as
well as clocking out the 608 pairs at the appropriate rate.

Thanks to Lance Wang <lance.lmwang@gmail.com>, Anton
Khirnov <anton@khirnov.net>, and Michael Niedermayer <michael@niedermayer.cc>
for providing review/feedback.
Signed-off-by: Devin Heitmueller <dheitmueller@ltnglobal.com>
Signed-off-by: Limin Wang <lance.lmwang@gmail.com>

Currently, the -1 (MR) preset is disallowed as it's taken as the preset
option not set, and the only way to access it was through svtav1-params.
Signed-off-by: Christopher Degawa <ccom@randomderp.com>
Signed-off-by: James Almer <jamrial@gmail.com>

Commit 55b81528 ("doc/filters: itemize crop examples") dropped the
quotation marks from these examples, but this one remained. Quotes are
actually needed to put the example into a command line or a program, but
removing it here makes the example consistent with the document.

Avoid compiling error if included by multiple sources.
Signed-off-by: Jianhui Dai <jianhui.j.dai@intel.com>
Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>

Fixes NULL pointer dereference later.

This allows for decimating large similar portions of a video while preserving small ones.

Similar to the decoder AVOptions, this is useful to show values from options
exported by the demuxer.
Signed-off-by: James Almer <jamrial@gmail.com>

Avoids the pointless overhead of transferring them to the main thread.

The two checks using eof_reached are testing whether more input can
possibly appear on this filtergraph input. InputFilterPriv.eof is the
more authoritative source for this information.

This code more properly belongs there.

It is shorter and more efficient.

It is not used outside of ffmpeg_filter.

It is not used outside of ffmpeg_filter.

It is not used outside of ffmpeg_filter.

When an input stream terminates and no frames were successfully decoded,
filtering code will currently configure the filtergraph using demuxer
stream parameters. Use decoder parameters instead, which should be more
reliable. Also, initialize them immediately when an input stream is
bound to a filtergraph input, so that these parameters are always
available (if at all) and filtering code does not need to reach into the
decoder at some arbitrary later point.

When no frames are ever seen by an encoder, encoder flush will do a
last-ditch attempt to configure its source filtergraph in order to at
least get the stream parameters. This involves extracting demuxer
parameters from filtergraph source inputs, which is
* a bad layering violation
* probably unreachable, because decoders are flushed before encoders,
  which should call ifilter_send_eof(), which will also set these
  parameters; however due to complex control flow it is hard to be
  entirely sure this code can never be triggered

Even if this code can actually be reached, it is probably better to
return an error as the comment above it says.

Replace it by simply calling choose_output() earlier.

These two functions are a part of a single logical action - determining
which, if any, output stream needs to be processed next. Keeping them
separate is a historical artifact that obscures what is actually being
done.