This update introduces a demux_packet_pool, allowing for the reuse of
previously allocated packets when needed.
sizeof(AVPacket) is not a part of the lavc public ABI, which prevents us
to allocate memory in larger blocks. However, we can substantially
decrease the amount of alloc/free operations during playback by reusing
both mpv's demux_packet and AVPacket.
This adjustment addresses the root cause of issue #12076, which,
although resolved upstream, did not fully tackle the persistent problem
of allocating small blocks of aligned memory. This issue largely stems
from the FFmpeg design of the AVPacket API. After this change memory
will no longer be allocated once cache limits is reached.
The demux_packet_pool is shared as a global pool of packets for a given
MPContext.
This change significantly speeds up the demuxer deinitialization,
benefiting file switching scenarios, especially when a large demuxer
cache is used.
See: #12294
See: #12563
Signed-off-by: Kacper Michajłow <kasper93@gmail.com>
When using --prefetch-playlist, if demuxer options are changed in the
time window between the start of prefetching and the playback of the
next file, the old values are used. This includes setting demuxer
options in legacy extension auto profiles.
Fix this by setting a flag when demuxer options change and not using the
prefetched data when that flag is true.
UPDATE_DEMUXER is not added to demux.c's options because those already
support updates while playing.
These were all deprecated in mpv 0.37.0 or earlier and are not
considered common enough options to warrant keeping the deprecated
mapping longer. Since demux_cue had only a single option in it, the
entire option substract is removed. This can be readded later if someone
wants to introduce a specific option to it again.
The purpose of osdep/io is to provide a wrapper for POSIX I/O functions
on Windows. The last 2 functions are utility functions which don't serve
this purpose.
Move them to a separate file.
--no-config should prevent loading user files of any type: configs,
cache, etc. For cache files, this case wasn't properly handled and it
was assumed they would always get something. vo_gpu's shader cache
actually already handles this, so it was left untouched. In theory,
demuxer cache should never have this issue because saving it to disk is
disabled by default (and likely that will never change), but go ahead
and change it for consistency's sake. Fixes some segfaults with
--no-config and various combinations of settings (particularly
--vo=gpu-next).
This adds cache as a possible path for mpv to internally pick
(~/.cache/mpv for non-darwin unix-like systems, the usual config
directory for everyone else). For gpu shader cache and icc cache,
controlling whether or not to write such files is done with the new
--gpu-shader-cache and --icc-cache options respectively. Additionally,
--cache-on-disk no longer requires explicitly setting the --cache-dir
option. The old options, --cache-dir, --gpu-shader-cache-dir, and
--icc-cache-dir simply set an override for the directory to save cache
files. If unset, then the cache is saved in XDG_CACHE_HOME.
Change all OPT_* macros such that they don't define the entire m_option
initializer, and instead expand only to a part of it, which sets certain
fields. This requires changing almost every option declaration, because
they all use these macros. A declaration now always starts with
{"name", ...
followed by designated initializers only (possibly wrapped in macros).
The OPT_* macros now initialize the .offset and .type fields only,
sometimes also .priv and others.
I think this change makes the option macros less tricky. The old code
had to stuff everything into macro arguments (and attempted to allow
setting arbitrary fields by letting the user pass designated
initializers in the vararg parts). Some of this was made messy due to
C99 and C11 not allowing 0-sized varargs with ',' removal. It's also
possible that this change is pointless, other than cosmetic preferences.
Not too happy about some things. For example, the OPT_CHOICE()
indentation I applied looks a bit ugly.
Much of this change was done with regex search&replace, but some places
required manual editing. In particular, code in "obscure" areas (which I
didn't include in compilation) might be broken now.
In wayland_common.c the author of some option declarations confused the
flags parameter with the default value (though the default value was
also properly set below). I fixed this with this change.
Somewhat similar to the old --cache-file, except for the demuxer cache.
Instead of keeping packet data in memory, it's written to disk and read
back when needed.
The idea is to reduce main memory usage, while allowing fast seeking in
large cached network streams (especially live streams). Keeping the
packet metadata on disk would be rather hard (would use mmap or so, or
rewrite the entire demux.c packet queue handling), and since it's
relatively small, just keep it in memory.
Also for simplicity, the disk cache is append-only. If you're watching
really long livestreams, and need pruning, you're probably out of luck.
This still could be improved by trying to free unused blocks with
fallocate(), but since we're writing multiple streams in an interleaved
manner, this is slightly hard.
Some rather gross ugliness in packet.h: we want to store the file
position of the cached data somewhere, but on 32 bit architectures, we
don't have any usable 64 bit members for this, just the buf/len fields,
which add up to 64 bit - so the shitty union aliases this memory.
Error paths untested. Side data (the complicated part of trying to
serialize ffmpeg packets) untested.
Stream recording had to be adjusted. Some minor details change due to
this, but probably nothing important.
The change in attempt_range_joining() is because packets in cache
have no valid len field. It was a useful check (heuristically
finding broken cases), but not a necessary one.
Various other approaches were tried. It would be interesting to list
them and to mention the pros and cons, but I don't feel like it.
Kacper Michajłow