This delays writing the moov until the first fragment is written,
or can be flushed by the caller explicitly when wanted. If the first
sample in all streams is available at this point, we can write
a proper editlist at this point, allowing streams to start at
something else than dts=0. For AC3 and DNXHD, a packet is
needed in order to write the moov header properly.

This isn't added to the normal behaviour for empty_moov, since
the behaviour that ftyp+moov is written during avformat_write_header
would be changed. Callers that split the output stream into header+segments
(either by flushing manually, with the custom_frag flag set, or by
just differentiating between data written during avformat_write_header
and the rest) will need to be adjusted to take this option into use.

For handling streams that start at something else than dts=0, an
alternative would be to use different kinds of heuristics for
guessing the start dts (using AVCodecContext delay or has_b_frames
together with the frame rate), but this is not reliable and doesn't
necessarily work well with stream copy, and wouldn't work for getting
the right initialization data for AC3 or DNXHD either.
Signed-off-by: NMartin Storsjö <martin@martin.st>

This allows writing edit lists even when track->entry == 0, if
the start times have been set.
Signed-off-by: NMartin Storsjö <martin@martin.st>

If fragments == 0 it means we haven't written any moov atom yet.
If the empty_moov flag is set, we already have written an empty moov
atom at startup. Thus, the check for empty_moov is redundant.

This is in preparation for allowing writing the moov atom later,
even when using the empty moov flag.
Signed-off-by: NMartin Storsjö <martin@martin.st>

Signed-off-by: NMartin Storsjö <martin@martin.st>

The pts and the corresponding duration is written in sidx
atoms, thus make sure these match up correctly.
Signed-off-by: NMartin Storsjö <martin@martin.st>

This allows setting the right fragment number if doing
random-access writing of fragments, and also allows reading the
current sequence number.
Signed-off-by: NMartin Storsjö <martin@martin.st>

This allows creating a later mp4 fragment without sequentially
writing the earlier ones before (when called from a segmenter).

Normally when writing a fragmented mp4 file sequentially, the
first timestamps of a fragment are adjusted to match the
end of the previous fragment, to make sure the timestamp is the
same, even if it is calculated as the sum of previous fragment
durations. (And for the first packet in a file, the offset of
the first packet is written using an edit list.)

When writing an individual mp4 fragment discontinuously like this
(with potentially writing the earlier fragments separately later),
there's a risk of getting a gap in the timeline if the duration
field of the last packet in the previous fragment doesn't match up
with the start time of the next fragment.

Using this requires setting -avoid_negative_ts make_non_negative
(or -avoid_negative_ts 0).
Signed-off-by: NMartin Storsjö <martin@martin.st>

This is mapped to the faststart flag (which in this case
perhaps should be called "shift and write index at the
start of the file"), which for fragmented files will
write a sidx index at the start.

When segmenting DASH into files, there's usually one sidx
at the start of each segment (although it's not clear to me
whether that actually is necessary). When storing all of it
in one file, the MPD doesn't necessarily need to describe
the individual segments, but the offsets of the fragments can be
fetched from one large sidx atom at the start of the file. This
allows creating files for the DASH ISO BMFF on-demand profile.
Signed-off-by: NMartin Storsjö <martin@martin.st>

Previously only tfra entries were added for the first track in each moof.

The frag_info array used for tfra can also be used for writing
other kinds of fragment indexes, where it's more important to
include all tracks.

When the separate_moof option is enabled (as in ismv), we write
a separate moof for each track, so this doesn't make any difference
in that case.
Signed-off-by: NMartin Storsjö <martin@martin.st>

A flag "dash" is added, which enables the necessary flags for
creating DASH compatible fragments.

When this is enabled, one sidx atom is written for each track
before every moof atom.
Signed-off-by: NMartin Storsjö <martin@martin.st>

By calling this after writing the moof the first time (for
calculating the moof size), we can avoid intermediate storage
of tfrf_offset in MOVTrack.
Signed-off-by: NMartin Storsjö <martin@martin.st>

When writing fragmented streams with an empty initial moov,
we won't have any samples in any tracks when writing the
moov atom, thus trust that any tracks that are added actually
will be present.
Signed-off-by: NMartin Storsjö <martin@martin.st>

This avoids a potential crash if writing a fragmented psp mp4
(which probably is only a hypothetical scenario).
Signed-off-by: NMartin Storsjö <martin@martin.st>

Signed-off-by: NMartin Storsjö <martin@martin.st>

QuickTime does support files with an empty initial movie
these days.
Signed-off-by: NMartin Storsjö <martin@martin.st>

Previously we wrote decoding timestamps here, while the specs
say it should be presentation timestamps.
Signed-off-by: NMartin Storsjö <martin@martin.st>

When using the new first_trun flag instead of checking the track id,
we don't need to have a special case for the separate_moof flag
any longer.

This simplifies the complicated codepath ever so slightly.
Signed-off-by: NMartin Storsjö <martin@martin.st>

In this case, shift tracks to start from zero instead (potentially
stretching the first sample in tracks that start later than the
first one).

Some software does not support edit lists at all, the adobe flash
player seems to be one of these. This results in AV sync errors when
edit lists are used to adjust AV sync.

Some players, such as QuickTime, don't respect the duration for
audio packets, so if an audio track starts later than the video
track and the first audio sample gets a duration longer than the
actual amount of data in it, the result will be out of sync.

Based on patches by Michael Niedermayer.
Signed-off-by: NMartin Storsjö <martin@martin.st>

We deviate slightly from the iso specs for these files.
Signed-off-by: NMartin Storsjö <martin@martin.st>

The tfdt atom shouldn't be needed in those cases, we already
write tfxd atoms for ismv anyway, which is roughly equivalent.

This avoids having to declare the iso6 brand for ismv files.
Signed-off-by: NMartin Storsjö <martin@martin.st>

ISO/IEC 14496-12:2012/Cor 1:2013 is explicit about how this should be
handled. All zeros doesn't mean that the full file has got a zero
duration, only that the track samples described within the initial moov
have got zero duration. An all ones duration means an indeterminate
duration.

Keep writing a duration consisting of all ones for the ISM mode -
older windows media player versions won't play a file if this is
zero. (Newer windows media player versions play either version fine.)
Signed-off-by: NMartin Storsjö <martin@martin.st>

Similarly to the omit_tfhd_offset flag added in e7bf085b, this
avoids writing absolute byte positions to the file, making them
more easily streamable.

This is a new feature from 14496-12:2012, so application support
isn't necessarily too widespread yet (support for it in libav was
added in 20f95f21 in July 2014).
Signed-off-by: NMartin Storsjö <martin@martin.st>

Signed-off-by: NMartin Storsjö <martin@martin.st>

Signed-off-by: NMartin Storsjö <martin@martin.st>

The custom IO flag actually never is set for muxers, only for
demuxers, so the check was pointless (unless a user intentionally
would set the flag to signal using custom IO).
Signed-off-by: NMartin Storsjö <martin@martin.st>

If one track doesn't have any samples within a moof, no traf/trun
is written for it. When the omit_tfhd_offset flag is set, none
of the tfhd atoms have any base_data_offset set, and the implicit
offset (end of previous track fragment data, or start of the moof
for the first trun) is used.
Signed-off-by: NMartin Storsjö <martin@martin.st>

These allow getting the absolute start timestamp of a fragment
without reading preceding timestamps. This fixes sync between
tracks if starting from fragments in different streams that don't
align exactly.

This also is a prerequisite for producing DASH content.
Signed-off-by: NMartin Storsjö <martin@martin.st>

Signed-off-by: NMartin Storsjö <martin@martin.st>

Signed-off-by: NMartin Storsjö <martin@martin.st>

This is necessary to get the right timestamp offset for content
that starts with dts != 0.

This currently only helps when writing fragmented files with a non-empty
moov atom. When writing an empty moov atom, we don't have any packets
yet, so we don't know the starting dts for the tracks.
Signed-off-by: NMartin Storsjö <martin@martin.st>

Signed-off-by: NMartin Storsjö <martin@martin.st>

This makes sure that audio preroll for e.g. AAC is signaled correctly.

Previously we only wrote the edit list correctly if we had negative
dts but started with pts == 0 (e.g. for video with B-frames).
Signed-off-by: NMartin Storsjö <martin@martin.st>

This reduces inter-library dependencies.

Signed-off-by: NDiego Biurrun <diego@biurrun.de>

Signed-off-by: NDiego Biurrun <diego@biurrun.de>

An encoding ("encd") box is required to tell QT that the string is UTF8

And add flag to muxer documentation.
Nero chapters break some taggers (mp3tag and iTunes).
Signed-off-by: NLuca Barbato <lu_zero@gentoo.org>