Some (de)muxers open additional files beyond the main IO context.
Currently, they call avio_open() directly, which prevents the caller
from using custom IO for such streams.

This commit adds callbacks to AVFormatContext that default to
avio_open2()/avio_close(), but can be overridden by the caller. All
muxers and demuxers using AVIO are switched to using those callbacks
instead of calling avio_open()/avio_close() directly.

(de)muxers that use the URLProtocol layer directly instead of AVIO
remain unconverted for now. This should be fixed in later commits.

Signed-off-by: NAnton Khirnov <anton@khirnov.net>

Also, extend the documentation about setting timestamps.

All encoders set pts and dts properly now (and have been doing that for
a while), so there is no good reason to do any timestamp guessing in the
muxer.

The newly added AVStreamInternal will be later used for storing all the
private fields currently living in AVStream.

`av_packet_unref` matches the AVFrame ref-counted API and can be used as
a drop in replacement.

Deprecate `av_free_packet`.

There are no formats supporting it anymore and it is deprecated.
Update the documentation accordingly.

During remuxing avcodec_copy_context() is discouraged as certain fields
(such as codec_tag) could reflect invalid values between input and
output contextes.

This is not an API change; the fields were explicitly declared private
before.
Signed-off-by: NAnton Khirnov <anton@khirnov.net>

This comment can be traced back to the initial commit from 2001,
and it seemed to be misleading/incorect already back then. (It
was used for normal, non-raw file formats already then.)
Signed-off-by: NMartin Storsjö <martin@martin.st>

This is the same logic as is invoked on AVFMT_TS_NEGATIVE,
but which can be enabled manually, or can be enabled
in muxers which only need it in certain conditions.

Also allow using the same mechanism to force streams to start
at 0.
Signed-off-by: NMartin Storsjö <martin@martin.st>

This makes the field consistent with AVInputFormat.mime_type and the
argument type of av_match_name.
Signed-off-by: NVittorio Giovara <vittorio.giovara@gmail.com>

It allows to configure how long will avformat_find_stream_info() wait
to get the first timestamp.

The only flags, for now, indicate if metadata was updated and are set after each call to
av_read_frame(). This comes with the caveat that, on stream start, it might not be set properly
as packets might be buffered in AVFormatContext.packet_buffer before being given to the user
in av_read_frame().
Signed-off-by: NAnton Khirnov <anton@khirnov.net>

It should provide a quicker guess for elementary streams provided
by http.

The callers should now set the stream timebase, not the codec one.

Signed-off-by: NAnton Khirnov <anton@khirnov.net>

Previously, AVStream.codec.time_base was used for that purpose, which
was quite confusing for the callers. This change also opens the path for
removing AVStream.codec.

The change in the lavf-mkv test is due to the native timebase (1/1000)
being used instead of the default one (1/90000), so the packets are now
sent to the crc muxer in the same order in which they are demuxed
(previously some of them got reordered because of inexact timestamp
conversion).

Provide f_strict for avconv usage.
Signed-off-by: NLuca Barbato <lu_zero@gentoo.org>

Use it instead of checking CODEC_FLAG_BITEXACT in the first stream's
codec context.

Using codec options inside lavf is fragile and can easily break when the
muxing codec context is not the encoding context.

@parblock is only supported in very recent Doxygen versions.

Remove some vague / incorrect statements and make the text more specific
and less confusing.

Remove some vague / incorrect statements and make the text more specific
and less confusing.

Currently ff_interleave_packet_per_dts() waits until it gets a frame for
each stream before outputting packets in interleaved order.

Sparse streams (i.e. streams with much fewer packets than the other
streams, like subtitles or audio with DTX) tend to add up latency and in
specific cases end up allocating a large amount of memory.

Emit the top packet from the packet_buffer if it has a time delta
larger than a specified threshold.

Original report of the issue and initial proposed solution by
mus.svz@gmail.com.

Bug-id: 31
Signed-off-by: NAnton Khirnov <anton@khirnov.net>

Those streams should never get any packets by definition.

avconv abuses the API by accessing AVStream.parser (which is private).
Removing AVStream.reference_dts in
2ba68dd0 breaks ABI compatibility for an
old avconv using a newer lavf. Fix this by adding a dummy field until
the next bump.