Try to read header elements stored at the end of the file in the order
of their position. (It would be nicer if mkv simply told us a range of
elements to parse, but it doesn't do that.)
This can potentially reduce seek elements, although I didn't check if
any real files trigger this. The real contribution by this change is
that it does not defer reading the CUE index if we need to seek to the
end of the file anyway. This can actually avoid 2 seeks when opening a
file and --start is used, and the file has other headers elements at the
end of the file (like tags).
Most contributors have agreed. This claims it's based on gstreamer code,
but this was LGPL at the time (and still is). Contributors whose code
was removed were not accounted for. There are still some potentially
problematic cases:
06eee1b67 is potentially the most problematic case. Most of these
changes are gone due to mpv not using BITMAPINFOHEADER anymore. Some
of the other changes are rather trivial. If someone contests this and
claims that copyrightable changes are left, the original change can
simply be reverted.
62bfae140 has only 2 lines left: a "char *name;" struct field, and a
line that prints a message. All other code was removed. The parsing code
in particular was made declarative, which replaced reading this element
explicitly (and other elements, see 1b22101c77). I'm putting the log
message under HAVE_GPL, but I don't think the declaration is
copyrightable, or the mere concept of reading this element. Redoing the
other 2 lines of code would result in the same program text.
d41e860ba was applied by someone who (potentially) disagreed. The patch
itself is from someone who did agree, though. It's unknown whether the
applier changed the patch. But it seems unlikely, and the change was
mostly rewritten.
50a86fcc3 all demux_mkv changes were reverted (old stdout slave mode)
3a406e94d same
2e40bfa13 the old MPlayer subtitle code was completely removed
316bb1d44 completely removed in 1cf4802c1d87f93d9d7 same
11bfc6780 relative seeks were removed in 92ba630796be54f4813 the corresponding demux_mkv code was removed in 5dabaaf093efd53eed6 all internal vobsub handling is now in FFmpeg
d7f693a20 removed in f3db4b0b93e8a1b3713 removed in 522ee6b783cfb890259 removed, see 6b1374b203 for analysis
c80808b5a same
Fixes seeking with:
https://bugs.chromium.org/p/chromium/issues/detail?id=497889
Haali also ignores the element's contents, and interprets its presence
as the block not being a keyframe. FFmpeg is going to have an equivalent
change.
I don't know yet whether the affected sample is valid - a reference
timestamp of 0 doesn't make too much sense to me.
TrueHD is a fucked up audio codec with extremely small frame sizes. Some
of these frames start with full headers, which are usually marked as
keyframes, and from which decoding can be started (or at least that's
what you'd expect).
So for such tracks we should probably trust the keyframe flags. Doesn't
really improve seek behavior, though.
Some files have audio tracks with packets that do not have a keyframe
flag set at all. I don't think there's any audio codec which actually
needs keyframe flags, so always assume an audio packet is a keyframe
(which, in Matroska terminology, means it can start decoding from that
packet).
The file in question had these set:
| + Multiplexing application: Lavf57.56.100 at 313
| + Writing application: Lavf57.56.100 at 329
Garbage produced by garbage...
There are other such files produced by mkvmerge, though. It's not
perfectly sure whether these have been produced by FFmpeg as well
(mkvmerge often trusts the information in the source file, even if it's
wrong - so other samples could have been remuxed from FFmpeg).
Fixes#3920.
Implementation-wise, the values from the demuxer/codec header are merged
with the values from the decoder such that the former are used only
where the latter are unknown (0/auto).
Matroska actually has lots of colorimetry metadata that video tracks can
use, including mastering metadata (HDR signal peak) etc.
This commit adds the EBML definitions and parses the most basic fields.
Note that nothing uses these fields yet, this commit is just adding the
necessary parsing and infrastructure.
Commit f72a900892 (and others) added support for ordered editions that
recursively refer to other ordered editions. However, this recursion
code incorrectly activated if the source files had ordered chapters
even if the main file only wanted to use them as raw video, resulting
in broken timeline info overall.
Ordered chapters can specify a ChapterSegmentEditionUID value if they
want to use a specific edition from a source file. Otherwise the
source is supposed to be used as a raw video file. The code checked
demuxer->matroska_data.num_ordered_chapters for an opened source file
to see whether it was using a recursive ordered edition, but demux_mkv
could enable a default ordered edition for the file using the normal
playback rules even if the main file had not specified any
ChapterSegmentEditionUID. Thus this incorrectly enabled recursion if a
source file had a default edition using ordered chapters. Check
demuxer->matroska_data.uid.edition instead, and ensure it's never set
if a file is opened without ChapterSegmentEditionUID.
Also fix what seems like a memory leak in demux_mkv.c.
Signed-off-by: wm4 <wm4@nowhere>
Don't access MPOpts directly, and always use the new m_config.h
functions for accessing them in a thread-safe way.
The goal is eventually removing the mpv_global.opts field, and the
demuxer/stream-layer specific hack that copies MPOpts to deal with
thread-safety issues.
This moves around a lot of options. For one, we often change the
physical storage location of options to make them more localized,
but these changes are not user-visible (or should not be). For
shared options on the other hand it's better to do messy direct
access, which is worrying as in that somehow renaming an option
or changing its type would break code reading them manually,
without causing a compilation error.
...and ignore it. The main purpose is for retrieving per-track
replaygain tags. Other than that per-track tags are not used or accessed
by the playback core yet.
The demuxer infrastructure is still not really good with that whole
synchronization thing (at least in part due to being inherited from
mplayer's single-threaded architecture). A convoluted mechanism is
needed to transport the tags from demuxer thread to user thread. Two
factors contribute to the complexity: tags can change during playback,
and tracks (i.e. struct sh_stream) are not duplicated per thread.
In particular, we update the way replaygain tags are retrieved. We first
try to use per-track tags (common in Matroska) and global tags
(effectively formats like mp3). This part fixes#3405.
Remove the explicit whitelisting of formats for refresh seeks. Instead,
check whether the packet position is somewhat reliable during demuxing.
If there are packets without position, or the packet position is not
monotonically increasing, then do not use them for refresh seeks.
This does not make sure of some requirements, such as deterministic
seeks. If that happens, mpv will mess up a bit on stream switching.
Also, add another method that uses DTS to identify packets, and prefer
it to the packet position method. Even if there's a demuxer which
randomizes packet positions, it hardly can do that with DTS. The DTS
method is not always available either, though. Some formats do not have
a DTS, and others are not always strictly monotonic (possibly due to
libavformat codec parsing and timestamp determination issues).
I've got a broken webm that fails to seek correctly with "--start=0".
The problem is that every index entry points to 1 byte before cluster
start (!!!). demux_mkv tries to resync to the next cluster, but since it
already has read 2 bytes with ebml_read_id(), it doesn't get the first
cluster, but the following one. Actually, it can be any amount of bytes
from 1-4, whatever happens to look valid at this essentially random byte
position.
Improve this by resyncing from the original position, instead of the one
after the EBML element ID has been attempted to be read.
The file shows the following headers:
| + Muxing application: google at 177
| + Writing application: google at 186
Indeed, the file was downloaded with youtube-dl. I can only guess that
Google got it completely wrong.
Now it will always be able to seek back to the start, even if the index
is sparse or misses the first entry.
This can be achieved by reusing the logic for incremental index
generation (for files with no index), and start time probing (for making
sure the first block is always indexed).
This reverts commit 503c6f7fd6.
There are situations where some decoders (MF apparently) always require
a timestamp. Also, this makes bitrate estimation more granular than
necessary. It seems it's better to try to detect fiels with broken
default durations explicitly instead. Or maybe something should be
added to smooth audio timestamps after filters.
This reverts commit af66fa8fa5.
The reverted commit caused AVCodecContext.channel_layout to be set,
while requesting stereo downmix will make libavcodec output a stupid
message:
ac3: Channel layout '5.1' with 6 channels does not match specified number of channels 2: ignoring specified channel layout
The same happens with --demuxer=lavf (without this change too).
I'm not quite sure what acrobatics are required to shut up libavcodec,
but for now revert the commit. It was a rather minor, almost cosmetic
issue, which I consider less important than clean CLI terminal output.
Ever since a change in mplayer2 or so, relative seeks were translated to
absolute seeks before sending them to the demuxer in most cases. The
only exception in current mpv is DVD seeking.
Remove the SEEK_ABSOLUTE flag; it's not the implied default. SEEK_FACTOR
is kept, because it's sometimes slightly useful for seeking in things
like transport streams. (And maybe mkv files without duration set?)
DVD seeking is terrible because DVD and libdvdnav are terrible, but
mostly because libdvdnav is terrible. libdvdnav does not expose seeking
with seek tables. (Although I know xbmc/kodi use an undocumented API
that is not declared in the headers by dladdr()ing it - I think the
function is dvdnav_jump_to_sector_by_time().) With the current mpv
policy if not giving a shit about DVD, just revert our half-working seek
hacks and always use dvdnav_time_search(). Relative seeking might get
stuck sometimes; in this case --hr-seek=always is recommended.
Commit 943f76e6, which already tried this, was very stupid: it didn't
actually override the samplerate for Opus, but overrode it for all
codecs other than Opus. And even then, it failed to use the overridden
samplerate. (Sigh...)
I think the conclusion is that AV_PKT_DATA_SKIP_SAMPLES is misdesigned
(at least for some formats), and an alternative mechanism using
durations would be better. (Combining it with a proper timebase would
keep sample-accuracy.)
FFmpeg can generate such files. It's unclear whether they're allowed by
Matroska. mkvinfo shows packet timestamps in both forms (one of them
must be a bug), and at last libavformat's demuxer treats timestamps
as signed.
This is mainly a refactor. I'm hoping it will make some things easier
in the future due to cleanly separating codec metadata and stream
metadata.
Also, declare that the "codec" field can not be NULL anymore. demux.c
will set it to "" if it's NULL when added. This gets rid of a corner
case everything had to handle, but which rarely happened.
Always preroll by default if the cue (index) information indicates
overlapping subtitles.
Increase the amount of maximum data it will skip to get such subtitles
to 10 seconds. Since the index information can reliably tell whether
reading earlier is needed, the maximum should be rarely actually used,
thus we can set it high. On the other hand, the "old" prerolling
mechanism always has to skip the maximum amount of data; thus the method
using the index gets its own option to control the maximum amount of
data to skip.
(As more and more files With newer mkvtoolnix versions are muxed, and
with this new and hopefully sane default established, these options can
probably be removed in the future.)
The demuxer infrastructure was originally single-threaded. To make it
suitable for multithreading (specifically, demuxing and decoding on
separate threads), some sort of tripple-buffering was introduced. There
are separate "struct demuxer" allocations. The demuxer thread sets the
state on d_thread. If anything changes, the state is copied to d_buffer
(the copy is protected by a lock), and the decoder thread is notified.
Then the decoder thread copies the state from d_buffer to d_user (again
while holding a lock). This avoids the need for locking in the
demuxer/decoder code itself (only demux.c needs an internal, "invisible"
lock.)
Remove the streams/num_streams fields from this tripple-buffering
schema. Move them to the internal struct, and protect them with the
internal lock. Use accessors for read access outside of demux.c.
Other than replacing all field accesses with accessors, this separates
allocating and adding sh_streams. This is needed to avoid race
conditions. Before this change, this was awkwardly handled by first
initializing the sh_stream, and then sending a stream change event. Now
the stream is allocated, then initialized, and then declared as
immutable and added (at which point it becomes visible to the decoder
thread immediately).
This change is useful for PR #2626. And eventually, we should probably
get entirely of the tripple buffering, and this makes a nice first step.
MPlayer traditionally always used the display aspect ratio, e.g. 16:9,
while FFmpeg uses the sample (aka pixel) aspect ratio.
Both have a bunch of advantages and disadvantages. Actually, it seems
using sample aspect ratio is generally nicer. The main reason for the
change is making mpv closer to how FFmpeg works in order to make life
easier. It's also nice that everything uses integer fractions instead
of floats now (except --video-aspect option/property).
Note that there is at least 1 user-visible change: vf_dsize now does
not set the display size, only the display aspect ratio. This is
because the image_params d_w/d_h fields did not just set the display
aspect, but also the size (except in encoding mode).
This is another regression of the recently added start time probing. If
a seek is executed after opening the file (but before reading any
packets), the first block is discarded instead of indexed. If there are
no other keyframes in the file, seeking will fail completely.
Fix it by seeking to the cluster start if there aren't any index entries
yet. This will read the skipped packet again.
Fixes#2498.
While it seemed like a pretty good idea at first, it's just a dead end
and works only in the simplest cases. While it may or may not help
slightly with audio sync mode, the display-sync mode already compensates
this in a better way. The main issue is that timestamps at this layer
are not in order, so it can look at single timestamps only.
MKV files can very well start with timestamps other than 0. While mpv
has support for such files in general, and demux_lavf enables this
feature, demux_mkv didn't export a start time.
Implement this by simply reading the first cluster timestamp. This in
turn is done by reading 1 block. While we don't need the block for this
prupose at all, it's the easiest way to get the cluster timestamp read
correctly without code duplication. In theory this could be wrong, and
a packet could start at a much later time, but in practice this won't
happen.
This commit also adds an option to disable this feature. It's not
documented because nobody should use it. (But I happen to have a need
for this.)
This affects the subtitle preroll mode during seeking. It could matter
somewhat with insane files with ten-thousands of subtitle events, which
now seem to pop up, and will avoid packet queue overflow.
Add a simplistic heuristic for detecting broken indexes. This includes
indexes with very few elements (apparently libavformat sometimes writes
such indexes, or used to), and indexes with broken timestamps.
The latter was apparently produced by very old HandBrake versions:
| + Muxing application: libmkv 0.6.1.2
| + Writing application: HandBrake 0.9.1
These broken files seem to be common enough that libavformat added a
workaround for them in 2008 (and maybe again in 2015). Apparently all
timestamps are multiplied with the file's tc_scale twice, and FFmpeg
attempts to fix them. We should throw away the whole thing.
Actually, this never happened, because there's logic for ignoring
duplicate header elements (which includes the seek index). This is
mostly for robustness and readability.
This doesn't work too well if sections of the file change to a different
framerate. It lowers our chances to guess the correct FPS in the display
sync code.
For normal playback, this (probably) doesn't help that much anyway,
except that the "estimated-vf-fps" property will regress in the simplest
mkv case. This will be fixed with the next commit.
The now disabled code will probably be removed; it's not useful anymore.
Handle a relatively recently introduced hack, that allows FLAC audio to
have arbitrary channel layouts, instead of just the predefined fixed
ones. This is actually supported by FFmpeg, but since the demuxer
(instead of the decoder) handles this in FFmpeg, we need to add special-
code to our mkv demuxer.
(The way FFmpeg does this seems a bit backwards, since now every demuxer
for a format that can handle FLAC needs to contain this logic as well.)
The FLAC hack is relatively terrible: we need to parse the FLAC headers,
look for a VorbisComment, parse the VorbisComment, and then retrieve
the magic WAVEFORMATEXTENSIBLE_CHANNEL_MASK entry. But the hack is
officially endorsed, as the official FLAC tools use it. (Although I
couldn't find a trace of it in the format specification. Should I be
surprised?)
Extend the --demuxer-mkv-probe-video-duration behavior to work with
files that are partial and are missing an index. Do this by finding a
cluster 10MB before the end of the file, and if that fails, just read
the entire file. This is actually pretty trivial to do and requires only
5 lines of code.
Also add a mode that always reads the entire file to estimate the video
duration.
If the EditionFlagOrdered is set, chapters without ChapterTimeEnd make
no sense. Ordered chapters will play the chapters in the order they
appear, but will play the ranges the chapters cover. So if the end time
is missing, the range is incomplete and it's not clear what should be
played. If you assume the start of the next chapter as end time, the
ordered flag will have no observable effect, so that's not a useful
assumption.
This fixes playback of a file which (apparently) had the
EditionFlagOrdered set accidentally, with normal chapters.
wm4
Niklas Haas
Uoti Urpala
Dmitrij D. Czarkoff
Kagami Hiiragi