It was originally for a different function av_destruct_packet_nofree:
MythTV@bf432d9#diff-4b6a432208acd44651f07cdde943169aba8c5611b26a83764ad784d00c250f7fR899

This reverts commit 049fabc.

Reduce changes to FFmpeg.

Instead of the internal FFmpeg header compat/cuda/dynlink_loader.h.  This leaves
only one internal FFmpeg header used by MythTV.

Per the comment on win32_dlopen() in FFmpeg/compat/w32dlfcn.h, Windows will now
additionally search the current directory for nvcuda.dll and nvcuvid.dll, which
FFmpeg considers less secure.

This is an atomic block and the order must be preserved:
 #include "libavutil/log.h"
 #define FFNV_LOG_FUNC(logctx, msg, ...) av_log(logctx, AV_LOG_ERROR, msg,  __VA_ARGS__)
 #define FFNV_DEBUG_LOG_FUNC(logctx, msg, ...) av_log(logctx, AV_LOG_DEBUG, msg,  __VA_ARGS__)
 #include <ffnvcodec/dynlink_loader.h>

 #include "libavutil/hwcontext_cuda.h"
must come after
 #include <ffnvcodec/dynlink_cuda.h>
which is also transitively included by #include <ffnvcodec/dynlink_loader.h>

This reverts commit 5f9b27c.

MythTV no longer uses that file, so remove the modification.

…h (part 1)

Since we don't need the full buffer, we could use avio_read_partial() instead.

Originally from 2003:
MythTV@ec136a9

…h (part 2)

…h (part 3)

I don't know if any of this is necessary since FFmpeg's avio API is already
buffered.  However, I did not investigate using avio directly with avio_open()
nor did I investigate what our buffer actually does.

I'm not sure why MythAVFormatBuffer::Seek() with Whence = SEEK_END did not ever
actually seek.

libavformat/avio.h says this about read_packet:
"
A function for refilling the buffer, may be NULL.
For stream protocols, must never return 0 but rather
a proper AVERROR code.
"

So I'm not sure the first return of 0 was correct.  AVERROR(EINVAL) is a more
useful return value for all of the functions, instead of 0.

They are const in mpegts.c.

The only STREAM_TYPE_* define used is STREAM_TYPE_PRIVATE_DATA.

STREAM_TYPE_AUDIO_DTS is already defined by FFmpeg to a different value.  0x8a
is used in MISC_types[].

STREAM_TYPE_AUDIO_HDMV_* defines are from:
MythTV@d15e482
They are now unused and FFmpeg has added the entries to HDMV_types[].

STREAM_TYPE_SUBTITLE_DVB is from:
MythTV@aaa9372#diff-ae852538fd61b663231c8bdda1fdbade40c97e8305401fcc6f1ad9f395efdf18
STREAM_TYPE_VBI_DVB is from:
MythTV@6da1854

However, the corresponding uses in MISC_types[] can never be used.
in mpegts_set_stream_info()
    pes->stream_type = stream_type;
...
        mpegts_find_stream_type(st, pes->stream_type, MISC_types);

mpegts_set_stream_info() is called either with stream_type = 0 or
stream_type = get8(&p, p_end)

0x100 and 0x101 exceed UINT8_MAX and thus will never be found in the search.

Use the names given in ETSI 300 468 and list all of the values used,
even if the defines aren't.

I'm not sure that the new name is correct since I don't have a copy of
ISO/IEC 13818-6.  However, it should be close.

From:
MythTV@cc2f9dd

Appears to be from 2006:
MythTV@156914d
MythTV@53d9721

Disabled in 2010:
MythTV@3cc5fc8#diff-2fb8a33ba832f242d27f19c9f25755b57af9807343e99dac77263c1c5ebc383a

Neither removed section has done anything since 2010:
MythTV@3cc5fc8#diff-2fb8a33ba832f242d27f19c9f25755b57af9807343e99dac77263c1c5ebc383a

Appears to have been from an FFmpeg merge in 2009:
MythTV@6d62e66

…ptor

This has no functional change since MythTV only uses the MythTV addition
AVStream::carousel_id if AVStream::codecpar::codec_id == AV_CODEC_ID_DSMCC_B.

originally from:
MythTV@a1d4d11
referencing:
https://code.mythtv.org/trac/ticket/1887

ISO/IEC 13818-1:2021 specifies a valid range of [0x0010, 0x1FFE] in
§ 2.4.4.6 Semantic definition of fields in program association section
and Table 2-3 – PID table

…ng, and pmt_scan_state

req_sid is from an FFmpeg merge:
MythTV@2a56a37#diff-2fb8a33ba832f242d27f19c9f25755b57af9807343e99dac77263c1c5ebc383a
removed from FFmpeg in
FFmpeg/FFmpeg@90d13e3

scanning and pmt_scan_state are from
MythTV@084e3f8

MpegTSContext::req_sid is only set by mpegts_read_header().

First, in pmt_cb() always create PMT filters.
Now we don't want to stop_parse early since that would prevent creating all the
PMT filters, so remove those changes to pat_cb() and pmt_cb().

MpegTSContext::pmt_scan_state is only tested in mpegts_read_header() and its use
is equivalent to `!ts->prg[i].pmt_found`.

Now MpegTSContext::scanning and MpegTSContext::pmt_scan_state are unused, so
remove them.

MpegTSContext::req_sid is now set but otherwise unused, so remove it as well.

Additionally, in mpegts_read_header() sid would cause an invalid index of -1 on
the first iteration.

The fallback code in mpegts_read_header() has been broken since
MythTV@0b0068c

sid != pmt_pid, so it was looking for the wrong filter in MpegTSContext::pids.

Disabling CRC is from:
MythTV@084e3f8
referencing
https://code.mythtv.org/trac/ticket/328

However, the sample does not trigger that fallback.

Deal with incomplete PMT streams in BBC iPlayer IPTV
MythTV@c11ee69
references
https://code.mythtv.org/trac/ticket/9926

The sample is unavailable and the issue was not in FFmpeg's unmodified demuxer,
so, following subsequent harmonization, I assume it is no longer an issue.  If
it still is, MythTV's other modifications should be looked at first.

There is one PMT per program, so add the stream_type to the corresponding
Program.  This means we no longer need to look at an MpegTSFilter.  The
searching logic in is_pmt_equal() is equivalent to that in pmt_equal_streams().
However, we now look at the entire PMT not just is_desired_stream()s.

Nothing now uses MpegTSContext::pid_cnt or MpegTSContext::pmt_pids, so remove
them and a lot of other now unused code.

See ISO/IEC 13818-1:2021 § 2.4.4.9 Program map table
Perhaps we could use TS_program_map_section()'s version_number and possibly
current_next_indicator instead of comparing the PMT ourselves?  Maybe by
modifying update_av_program_info()?

export_pmt() would probably need
if (old_version == -1 || old_version != version)
also its buffer should probably be moved to AVProgram since each program has a
different PMT.

Similarly streams_changed() should have a program_number parameter, since we
probably only care about one program at a time.

This can be a problem when there is more than one program in one file, e.g.
a full TS capture with multiple digital subchannels.

The `#if`ed out log in AutoSelectAudioTrack was broken; I replaced it with
something that should be similar.

This is clearer than the infinite loop with breaks (effectively gotos).

This is a MythTV addition that exports the PMT from an MPEG-TS.  However, each
program has its own PMT so having a single pmt_section in AVFormatContext is not
correct when there are multiple programs in the stream.  Previously, each PMT
overwrote the last one.

Adapt AvFormatDecoder to look in AVProgram.

In my limited testing, the PMT did not seem necessary for ATSC captions.

MythAVBufferRef: Satisfy the rule of five; however, since nullptr is now
allowed, the newly defined constructors and operators are unused.  The compiler
generated ones were causing use after free segmentation faults.

This is an int to match type with AVProgram.  In mpegts.c, SectionHeader::id is
a uint16_t as ISO/IEC 13818-1:2021 specifies for program_number.

This allows us to ignore stream changes in programs that are not being watched
when there is more than one program.

Regarding the changes to mpeg.c:
Originally from:
dvb/ac3 patches 1, 2, and 3 from Mark Anderson
MythTV@87795f6

changed in:
Refs #8134. internal dvd player. resolve problem where pcm_s16be audi…
MythTV@e64371a

change reverted in:
Refs #8134. revert most of [24239]. Anduin withers reported it makes …
MythTV@a3d6e14

referencing: #8134 (internal dvd player: pcm_s16be improperly detected as pcm_dvd audio codec.) – MythTV
https://code.mythtv.org/trac/ticket/8134

An MPEG Program Stream can only have one program, so FFmpeg does not create an
AVProgram for it.  Thus av_find_program_from_stream() (and therefore
get_current_AVProgram()) will always return nullptr, so avprogram_id will be
ignored.

The calling conventions of functions with "C" and "C++" language linkage are not
necessarily the same; however, in practice they are, so
AvFormatDecoder::streams_changed() could be used directly.  Doing it correctly
still eliminates the use of a friend function and its double declaration at only
the cost of an extra function call, which doesn't matter since streams_changed()
is only called very rarely.

by using the PMT's version_number (and current_next_indicator) to determine when
to call streams_changed().  (FFmpeg already checks the current_next_indicator
in pmt_cb() before the call to update_av_program_info().)

The only change is the first seen PMT for each program will now never call
streams_changed().  is_pmt_equal() would return 0 for the first seen PMT for
each program when opening the file, but streams_changed is null at that point.

This may prevent a call to streams_changed() when a new PAT version adds a
program.  However, MythTV does not fully support multiple programs in a single
transport stream, so this is acceptable.  The new PAT may also remove the
currently playing program, which the PMT code cannot detect.

It does nothing since pmt_cb() already closes the already existing filter before
calling and the call in handle_packet() will only occur when
`ts->pids[pid] == NULL`, i.e. there is no filter to close.

It was originally from:
PMT tracking in ffmpeg patch from danielk.
MythTV@236872a

instead of AVCodecContext::reordered_opaque and AVFrame::reordered_opaque, which
have been removed and as far as I can tell were just passed around and unused
by FFmpeg.

Uncommenting the dump() statement shows 3140ms.
ffprobe version 6.1.1-3ubuntu5 also shows 3.14 seconds, so FFmpeg now thinks
the file is 25ms shorter.

…ings

also fixed a typo from 7a6b478,
where the left channel was set to 0 twice instead of setting both
the left and right value to 0.

…y_frame

They were only used by MythTranscodePlayer so move them there.

UpdateStoredFrameNum(), WriteStoredData(), ClearStoredData()

and fix Doxygen syntax for other functions.

and eliminate unnecessary transitive includes of those files.

The first return ensures (available < count) is always true.

If m_ateof is true, then Count = available, which means (available < count) is
false and all subsequent conditionals are false.

Now, (available < count) is only needed for the while loop condition.

FFmpeg removed the used function and the recommendation was to use
AVCodecContext.hw_frames_ctx or hw_device_ctx instead.  However,
the code is already using those, so I don't know what it was supposed
to be doing.

… and key_frame

This reverts commit db3dfa505a2a5a7e2b6ff898f9c3ad5d74fbf01a.

I am not sure the "optimization" was correct and removing the customization
appears to have no effect of any kind.  My MHEG sample did not trigger the log
message for "All DSM info found".

The code in libavcodec/mpeg12dec.c will never create a cc_type of 2 for SCTE-20
and cc_type is guaranteed to be less than 2 otherwise by the if condition.

AvFormatDecoder::m_invertScteField is now always 0, so remove it.

AvFormatDecoder::m_lastScteField is now set but unused, so remove it.

…captions

see mpeg_decode_a53_cc()

Differences:
FFmpeg does not have the initial two bytes that MythTV added to signal valid and
length.

FFmpeg will only use the first type of embedded CC that it sees, whereas MythTV
would switch between ATSC and SCTE-20 under certain conditions.  If multiple
types were present MythTV would concatenate them.

FFmpeg allows forcing the subtitle format with the cc_format option in mpeg12dec.c.

DVD CC:
FFmpeg does not check p[4]

ATSC A/53:
FFmpeg checks the process_cc_data_flag in p[5].

SCTE-20:
FFmpeg ignores line_offset, which MythTV ensures is 11 for line 21 data.

FFmpeg does not set one_bit or the 4 reserved bits before cc_valid and cc_type
(cc608hdr vs cap[0]), but these are only to avoid emulating start codes and are
not checked, so it doesn't matter.

p[0] == 0x05 && p[1] == 0x02:
Moved to mpeg_decode_a53_cc().

Originally from:
Fixes #2481, by applying patch from kenny at the-b org. This adds dec…
MythTV@49d3294

Referencing:
https://code.mythtv.org/trac/ticket/2481

Modified in:
Simplify DTV CEA-608 handling a bit & add some range checking.
MythTV@be6a2b4

Some tweaks to cc implementation in mpeg12.c: make the C ANSI compati…
MythTV@77cff32

See also:
https://github.com/CCExtractor/ccextractor/blob/master/src/lib_ccx/es_userdata.c

MythTV:
SCTE-20 encapsulates CTA-608, which is where XDS is defined, so I don't know why
the condition was specific to SCTE-20.

This reverts commit 641109a.

David Hampton confirmed on the mailing list that this change is no longer
necessary on FreeBSD 13/14/15.

…Android)'

Neither header is checked by FFmpeg's configure and neither HAVE_EGL_EGL_H
nor HAVE_GLES2_GL2_H is defined.  FFmpeg/configure has not tested those since
MythTV@018be3f
in 2018.

FFmpeg's configure never tested eglGetProcAddress and thus would never define
HAVE_EGLGETPROCADDRESS.

MythTV's configure does check them and (myth)config.h does define HAVE_EGL_EGL_H,
HAVE_GLES2_GL2_H, and HAVE_EGLGETPROCADDRESS; however, FFmpeg does not use
mythconfig.h, using its own config.h instead, probably since the decoupling of
MythTV and FFmpeg's configure in
MythTV@9563786
in 2018.

by merging the code into AvFormatDecoder::RemoveAudioStreams() and replacing
ff_flush_packet_queue() with avformat_flush().

The original code could have accessed out of bounds if the first stream was an
audio stream, since i would have been -1 on the next iteration.  This would also
cause it to recheck previously checked streams when a stream was removed.

By setting the index first, we don't have to iterate twice to renumber the streams.

Slightly more is reset by avformat_flush(), see libavformat/seek.c, compared to
just ff_flush_packet_queue(), but it is a public function and resetting the
extra values is probably better since it more fully resets the AVFormatContext.
Additionally, the AVFormatContext is now only reset once instead of after
removing each stream.

StreamInfo::m_av_substream_index is only used for kTrackTypeAudio.  It is no
longer set to 0 by:
mythdvddecoder.cpp
AvFormatDecoder::ScanStreams() for AVMEDIA_TYPE_SUBTITLE

StreamInfo::m_orig_num_channels is only used by AvFormatDecoder::GetTrackDesc()
to print the number of audio channels for kAudioTypeNormal.
The following no longer set m_orig_num_channels to 0:
mythdvddecoder.cpp
cc708reader.cpp
decoderbase.cpp
avformatdecoder.cpp

StreamInfo::m_easy_reader and m_wide_aspect_ratio were unused but set by:
AvFormatDecoder::ScanATSCCaptionStreams() (incorrectly, setting
m_orig_num_channels = easy_reader and m_easy_reader = wide_aspect_ratio)

AvFormatDecoder::ScanStreams() for AVMEDIA_TYPE_AUDIO (appeared to set m_easy_reader
in an unused attempt to flag the second StreamInfo for dual mono audio)

decoderbase.cpp: I don't know why one of the default CC608 set m_language_index
to 2, but it is not used for closed captions.

If continue is DVD specific and from
MythTV@8bcef59

AVStream::id will never be negative for MPEG-TS or MPEG-PS.

It was a copy of a value from AVCodecParameters and was only used for printing.

If the channel count from FFmpeg is wrong, add this to GetTrackDesc() to get the
value from libdvdnav:

if (m_ringBuffer->IsDVD())
    channels = m_ringBuffer->DVD()->GetNumAudioChannels(m_tracks[kTrackTypeAudio][TrackNo].m_stream_id);

When attempting to upstream the change before, it was recommended to instead
use AV_CHANNEL_ORDER_CUSTOM with two AV_CHAN_FRONT_CENTER channels. See
https://patchwork.ffmpeg.org/project/ffmpeg/patch/[email protected]/

audiotoolboxdec.c will no longer flag dual_mono since it uses
AV_CHANNEL_ORDER_UNSPEC.

SetupAudioStreamSubIndexes() will create or destroy the second StreamInfo for
the second substream, leaving the duplicate StreamInfo from ScanStreams()
untouched, allowing playing both channels as stereo.