Even with -Dgpl=false, some files including the documentation,
mpv.desktop, and some key binding files are still being built.
This means that mpv as a whole might not be LGPL even when the
program itself is LGPL.
Also the description that mpv is licensed under LGPLv2.1+
"if built with the -Dgpl=false configure switch" is incorrect
as it appears to give a license grant as long as the switch is
used, regardless if there is a bug in the build system that
results in a GPL file being compiled in.
Change the description to clarify this.
Remove some of the features that no longer exist or aren't directly
supported in the mpv code: Linux analog TV (DVB still supported),
SMB, bootstrap.py.
Also fix the path for mpv.desktop.
This required libsmbclient, which is a heavy dependency, and as a
library, has all kinds of problems. For one, the API requires completely
unacceptable global state (in particular, leaks auth state), and is not
thread-safe (meaning concurrent reads to multiple files block each
other).
There are better replacements: you can use the Linux kernel's builtin
CIFS support, fusesmb, or contribute supoport for libdsm.
Basically, both the license of the file and the preferred license of the
project (LGPLv2.1+) counts. I'm doing that so that files with more
liberal licenses don't get infected by LGPL, but allow copy & pasting to
LGPL source files without jumping through lawyer bullshit hoops.
Mention this in Copyright too.
This does what af_volume used to do. Since we couldn't relicense it,
just rewrite it. Since we don't have a new filter mechanism yet, and the
libavfilter is too inconvenient, do applying the volume gain in ao.c
directly. This is done before handling the audio data to the driver.
Since push.c runs a separate thread, and pull.c is called asynchronously
from the audio driver's thread, the volume value needs to be
synchronized. There's no existing central mutex, so do some shit with
atomics. Since there's no atomic_float type predefined (which is at
least needed when using the legacy wrapper), do some nonsense about
reinterpret casting the float value to an int for the purpose of atomic
access. Not sure if using memcpy() is undefined behavior, but for now I
don't care.
The advantage of not using a filter is lower complexity (no filter auto
insertion), and lower latency (gain processing is done after our
internal audio buffer of at least 200ms).
Disavdantages include inability to use native volume control _before_
other filters with custom filter chains, and the need to add new
processing for each new sample type.
Since this doesn't reuse any of the old GPL code, nor does indirectly
rely on it, volume and replaygain handling now works in LGPL mode.
How to process the gain is inspired by libavfilter's af_volume (LGPL).
In particular, we use exactly the same rounding, and we quantize
processing for integer sample types by 256 steps. Some of libavfilter's
copyright may or may not apply, but I think not, and it's the same
license anyway.
Now using libavfilter filters directly.
The rotation case is a bit lazy, because it uses the slow vf_rotate
filter in all cases, instead of using special filters for 90° step
rotations.
They were added to the "to deleted" list and never relicensed, because I
thought I'd delete them early. But it's possible that they'll stay in
mpv for a longer time, so relicense them. Still leaving them as
deprecated and scheduled for removal, so they can still be dropped once
there is a better way to deal with them, if they get annoying, or if a
better mechanism is found that makes them unnecessary.
All contributors agreed. There are some minor changes by people who did
not agree, but these are all not relevant or have been removed.
Almost all of them had their guts removed and replaced by libavfilter
long ago, but remove them anyway. They're pointless and have been
scheduled for deprecation.
Still leave vf_format (because we need it in some form) and vf_sub (not
sure).
This will break some builtin functionality: lavfi yadif defaults are
different, auto rotation and stereo3d downconversion are broken. These
might be fixed later.
We want to drop vf_scale, but we still need a way to auto convert
between imgfmts. In particular, vf.c will auto insert the "scale" filter
if the VO doesn't support a pixfmt.
To avoid chaos, create a new vf_convert.c filter, based on vf_scale.c,
but without the unrelicensed code parts. In particular, this filter does
not do scaling and has no options. It merely converts from one imgfmt to
another, if needed.
There has been no new developments or agreements, but I was uncertain
about the copyright status of them. Thus this part of code was marked as
being potentially GPL, and was not built in LGPL mode. Now I've taken a
close look again, and decided that these can be relicensed using the
existing relicensing agreements.
OSD level 3 was introduced in commit 8d190244, with the author being
unreachable. As I decided in commit 6ddd95fd, OSD level 3 itself can
be kept, but the "osd" command had to go, and the "rendering" of OSD
level 3 (the HAVE_GPL code in osd.c) was uncertain. But the code for
this was rewritten: instead of duplicating the time/percent formatting
code, it was changed to use common code, and some weird extra logic was
removed. The code inside of the "if" is exactly the same as the code
that formats the OSD status line (covered by LGPL relicensing).
The current commands for adding/removing sub/audio tracks more or less
originated from commit 2f376d1b39, with the author being unreachable.
But the original code was very different, mostly due to MPlayer's
incredibly messy handling of subtitles in general. Nothing of this
remains in the current code. Even the command declarations were
rewritten. The commands (as seen from the user side) are rather similar
in naming and semantics, but we don't consider this copyrightable. So it
doesn't look like anything copyrightable is left.
The add/cycle commands were more or less based on step_property,
introduced in commit 7a71da01d6, with the patch author disagreeing with
the LGPL relicensing. But all code original to the patch has been
replaced in later mpv changes, and the original code was mostly copied
from MP_CMD_SET_PROPERTY anyway. The underlying property interface was
completely changed, the error handling was redone, and all of this is
very similar to the changes that were done on SET_PROPERTY. The command
declarations are completely different in the first place, because the
semantic change from step to add/cycle. The commit also seems to have
been co-authored by reimar to some degree. He also had the idea to
change the original patch from making the command modify a specific
property to making it generic.
(The error message line, especially with its %g formatting, might
contain some level of originality, so change that just to be sure.
This commit Copies and adapts the error message for SET_PROPERTY.)
Although I'm a bit on the fence with all the above things, it really
doesn't look like there's anything substantial that would cause issues.
I thus claim that there is no problem with changing the license to LGPL
for the above things. It's probably still slightly below the standard
that was usually applied in the code relicensing in mpv, but probably
still far above to the usual in open source relicensing (and above
commercial standards as well, if you look what certain tech giants do).
Looks like this is covered by LGPL relicensing agreements now.
Notes about contributors who could not be reached or who didn't agree:
Commit 7fccb6486e has tons of mp_msg changes look like they are not
copyrightable (even if they were, all mp_msg calls were rewritten in
mpv times again). The additional play() change looks suspicious, but
the function was rewritten several times anyway (first time after that
commit in 4f40ec312).
Commit 89ed1748ae was rewritten in commit 325311af3 and then again
several times after that. Basically all this code is unnecessary in
modern mpv and has been removed.
No code survived from the following commits: 4d31c3c53, 61ecf838f2,
d38968bd, 4deb67c3f. At least two cosmetic typo fixes are not
considered as well.
Commit 22bb046ad is reverted (this wasn't a valid warning anyway, just
a C++-ism icc applied to C). Using the constants is nicer, but at least
I don't have to decide whether that change was copyrightable.
Unfortunately I'm also adding the full text of the LGPL license text,
because the GPL one was already present in this repository, and I don't
want to imply that the GPL somehow has priority.
Rename --enable-preliminary-lgpl2 to --enable-gpl. This concludes the
relicensing. Some things are still to do (relicensing some still-GPL
optional code), but we consider the code included by --enable-gpl to be
fully relicensed.
The relicensing was performed by asking every known author for
permission for relicensing it to LGPL version 2.1 "or later". If an
author could not be contacted or permission could not be obtained, and
the contribution was considered relevant for copyright purposes, the
affected code was either excluded from LGPL mode (not built), or removed
or rewritten. This is the standard in open source relicensing processes.
Keep in mind that using LGPL mode is still on the user's own risk. Even
though I claim that the relicensing was pretty clean and thorough
(measured on the standards of the open source community¹), and I
followed the advice of some actual experts, there is still a residual
uncertainty due to the fact that I'm not an all-knowing entity (authors
could have taken someone else's code and pretend it's their own) nor a
lawyer (meaning I might lack associated authority or expertise), and the
fact that the judicial system is far from deterministic. The relicensing
was performed merely to the best of my knowledge. I reject all
responsibility outside of that.
This commit also cleans up the "Copyright" file to reflect the finalized
relicensing process.
¹ Not to imply that the standards of commercial companies are much
higher. Some major tech companies get away with stuff I would not
consider clean.
See #2033.
iive agreed to relicense things that are still in mpv to LGPLv2.1. So
change the licenses of the affected files, and rename the configure
switch for LGPL mode to --enable-preliminary-lgpl2.
(The "preliminary" part will probably be removed from the configure
switch soon as well.)
Also player/main.c hasn't had GPL parts since a few commits ago.
Originally mpv vaapi support was based on the MPlayer-vaapi patches.
These were never merged in upstream MPlayer. The license headers
indicated they were GPL-only. Although the actual author agreed to
relicensing, the company employing him to write this code did not, so
the original code is unusable to us.
Fortunately, vaapi support was refactored and rewritten several times,
meaning little code is actually left. The previous commits removed or
moved that to GPL-only code. Namely, vo_vaapi.c remains GPL-only. The
other code went away or became unnecessary mainly because libavcodec
itself gained the ability to manage the hw decoder, and libavutil
provides code to manage vaapi surfaces. We also changed to mainly using
EGL interop, making any of the old rendering code unnecessary.
hwdec_vaglx.c is still GPL. It's possibly relicensable, because much of
it was changed, but I'm not too sure and further investigation would be
required. Also, this has been disabled by default for a while now, so
bothering with this is a waste of time. This commit simply disables it
at compile time as well in LGPL mode.
See "Copyright" file for caveats.
This changes the remaining "almost LGPL" files to LGPL, because we think
that the conditions the author set for these was finally fulfilled.
Both the video equalizer command/option glue, which drives this filter,
as well as the filter itself are slightly GPL contaminated. So it goes.
After this commit, "--vf=eq" will actually use libavfilter's vf_eq (if
FFmpeg was compiled in GPL mode), but it has different options and will
not listen to the equalizer VOCTRLs.
Actually contains some code fragments by Michael Niedermayer (command
line stuff, video equalizer), thus it can be LGPL only once the formal
requirement of mpv's core being LGPL is fulfilled.
While I'm not particularly attached to this, the history is pretty
simple, and all relevant authors have agreed.
2f004875: removed in 2c693a47, patch author was not asked.
1ef239a4: removed, author was not asked.
All relevant authors have agreed.
I'm removing the NV12 FourCC, which was added in f910f3d9 by someone who
was not contacted for the relicensing. I doubt the remaining code is
copyrightable (basically all what remains the fact is that NV12 uses the
same amount of space like YV12), but in this case I feel more
comfortable removing it.
Might contain some trace amounts of "michael"'s copyright, who agrees
with LGPL only once the core is relicensed - but with the core already
mostly relicensed, I'm changing the license header to LGPL, and only
marking this in the "Copyright" file.
cehoyos, who did not agree to the relicensing, added bcb5c78ce3. If
there was copyright, we consider it gone, because the table changed. It
does not map file extension to a FourCC anymore, and codecs.conf is
gone. The new mapping is a libavcodec codec name (happens to be the same
as the file extension).
The same applies to commits 60ecafec, b749836b, 5b3e3be1. None of these
authors were contacted. These were before the code was replaced with a
table (in d0326807). The parts outside of demux_mf.c were removed a long
time ago. Like in the previous comment, we don't think any copyright
applies at least to the new code (at least after the FourCC removal).
iive authored 0aa37a0d, which is probably still left in some form, and
makes demux_mf.c "LGPL 3 or later".
stream_avdevice.c (unrelated) has been marked as LGPL before.
These files have all in common that they were fully or mostly taken from
mplayer.c. (mplayer.c was a huge file that contains almost all of the
playback core, until it was split into multiple parts.) This was
probably the hardest part to relicense, because so much code was moved
around all the time.
player/audio.c still does not compile. We'll have to redo audio
filtering. Once that is done, we can probably actually provide an
actual LGPL configure switch.
Here is a relatively detailed list of potential issues:
8d190244: author did not reply, parts were made GPL-only in a previous
commit.
7882ea9b: author could not be reached, but the code is gone. wscript
still has --datadir switch, but I don't think this is relevant to
copyright.
f197efd5: unclear origin, but I consider the code gone anyway (replaced
with generic OSD mechanisms).
8337d9c2: author did not reply, but only the option still exists (under
a different name), other code was removed.
d8fd7131: did not reply. Disabled in a previous commit.
05258251: same author as above. Both fields actually seem to have
vanished (even when tracking renames), so no action taken.
d459e644, 268b2c1a: author did not reply, but we reuse only the options
(with different names and slightly or fully different semantics, and
completely different implementations), so I don't think this is relevant
for copyright.
09e742fe, 17c39c4e: same as above.
e8a173de, bff4b3ee: author could not be reached. The commands were
reworked to properties, and the code outside of the TV code were moved
back to the TV code. So I don't think copyright applies to the current
command.c parts (mp_property_tv_color, mp_property_tv_freq,
mp_property_tv_scan). The TV parts remain GPL.
0810e427: could not be reached. Disabled in a previous commit.
43744a2d: unknown author, but this was replaced by dynamic alloc (if the
change is even copyrightable).
116ca0c7: unknown author; reasoning see input.c relicensing commit.
e7e4d1d8: these semantics still exist, but as generic code, and this
code was fully removed.
f1175cd9: the author of the cited patch is unknown, and upon inspection
it turns out that I was only using the idea to pause the player on EOF,
so I claim it's not copyright relevant.
25affdcc: author could not be reached (yet) - but it's only a function
rename, not copyrightable.
5728504c was committed by Arpi (who agreed), but hints that it might be
by a different author. In fact it seems to be mostly this patch:
http://lists.mplayerhq.hu/pipermail/mplayer-dev-eng/2001-November/002041.html
The author did not respond, but it all seems to have been removed later.
It's a terrible mess though. Arpi reverted the A-V sync code at first,
but left the RTC code for a while. The following commits remove these
changes 100%: 14b35442, 7181a091, 31482783, 614f8475, df58e822.
cehoyos did explicitly not agree to LGPL, but was involved in the
following changes:
c99d8fc8: applied a patch and didn't modify it, the original author
agreed.
40ac0d31: author could not be reached, but all code is gone anyway. The
"af" command has a similar function, but works completely different and
actually reuses a mechanism older than this patch.
54350436: applied a patch, but didn't modify it, except for adding a
German translation, which was removed later.
a2dda036: same situation as above
240b743e: this was made GPL-only in a previous commit
7b25afd7: same as above (for now)
kirijua could not be reached, but was a regular patch contributor:
c2c997fd: video equalizer code move; probably not copyrightable. Is GPL
due to Nick anyway.
be54f481: technically, this became the audio track property later. But
all what is left is the fact that you pass a track ID to it, so consider
the original coypright non-relevant.
2f376d1b: this was rewritten in b7052b43, but for now we can afford to
be careful, so this was marked as GPL only in a previous commit.
43844d09: remaining parts in main.c were reverted in a previous commit.
anders has mostly disagreed with the LGPL relicensing. Does not want
libaf to become LGPL, but made some concessions. In particular, he
granted us permission to relicense 4943e9c52c and 242aa6ebd4. We also
consider some of his changes remaining in mpv not relevant for copyright
(such as 735de602 - we won't remove the this option completely). We will
completely remove his other contributions, including the entire audio
filter chain. For now, this stuff is marked as GPL only. The remaining
question is how much code in player/audio.c (based on the former
mplayer.c and dec_audio.c) is under his copyright. I made claims about
this in a previous commit.
Nick(ols) Kurshev, svn username "nick" and "nickols_k", could not be
reached. He had a lot of changes in early MPlayer. It seems all of that
was removed, at least in mpv. His main work, like VIDIX or libswscale
work, does not exist in mpv anymore, but the changes to mplayer.c and
other core parts still deserve attention:
a4119f6b, fb927549, ad3529b8, e11b23dc, 5f2178be, 93c371d5: removed in
b43d67e0, d1628d12, 24ed01fe, df58e822.
0a83c6ec, 104c125e, 4e067f62, aec5dcc8, b587a3d6, f3de6e6b: DR, VAA, and
"tune" stuff was fully removed later on or replaced with other
mechanisms.
340183b0: screenshots were redone later (the VOCTRL was even removed,
with an independent implementation using the same VOCTRL a few years
later), so not relevant anymore. Basically only the 's' shortcut remains
(but not its implementation).
92c5c274, bffd4007, 555c6766: for now marked as GPL only in a previous
commit.
Might contain some trace amounts of "michael"'s copyright, who agreed to
LGPL only once the core is relicensed. This will still be respected, but
I don't think it matters at this in this case. (Some code touched by him
was merged into mplayer.c, and then disappeared after heavy
refactoring.)
I tried to be as careful and as complete as possible. It can't be
excluded that amends to this will be made later.
This does not make the player LGPL yet.
The I binding was removed from input.conf (although it's probably not
copyrightable, but still).
bootstrap.py has a bunch of authors which probably make the licensing
situation a pain - but it's not integral part of the build system or the
source code, so it doesn't matter for a LGPL core.
I checked and cleaned up the build system in the last few commits. There
was the possibility that parts of it were based on actual code of the
old "configure" file, in particular with the waftools/fragments/ files
(it turned out some were, some even not covered by LGPL agreements).
This was checked, so I'm confident only the commit mentioned in the
Copyright file holds back proper LGPL licensing of it. (And I guess I
have to wait for a reply.)
I checked the English translations. There used to be help_mp-en.h (or
help_mp.h earlier), which was part of the source code, and which
contained most terminal and GUI messages. This was done for the purpose
of localization, but all localizations were dropped at one point in
mplayer2 development. At this point, the message defines were moved back
to the source code. (While in the years before that, they were moved
from the source code to the file where applicable.) I didn't check
help_mp-en.h when it was merged back. There was the possibility that
someone might have changed one of the English messages (i.e. added his
copyright to it), which then was copied back to the source code, without
accounting for that copyright. Upon checking the history now, it seems
this didn't happen for any code that we want to relicense to LGPL (in
fact, it happened to some messages in the DVD code only).
Although the origins lie somewhere in libaf, which was written by
"anders" and who explicitly disagreed with the LGPL relicensing, we can
change the license of these files, because all code was written by
"alex", who agreed with the relicensing.
The only things that remain from anders' code is the AF_FORMAT_ and af_
prefixes (see e.g. 66f4e563). It was alex who redid this file and added
the format identifiers we have today (507121f7). It's also nice to see
that alex actually claimed copyright on format.c (221a599f). In commit
efb50cab even the bitmask concept (which anders introduced with his
early af_format.c code) was removed, and essentially all lines and
symbols by anders were dropped.
To put it into perspective: the original af_format code was for
converting actual sample data and relied on OSS sample format
identifiers, mpv's format.c/h provides its own sample formats, but
does not do any data conversion.
Remove an now inaccurate comment from format.c (it somehow even survived
the typo that was present in the original commit). Also remove most of
the format.c include statements - most of them are technically anders'
code. We keep limits.h though.
As usual, the history of these files is a bit murky. It starts with the
initial commit. (At which some development had already been done,
according to the AUTHORS and ChangeLog files at the time, we should be
but covered with relicensing agreements, though.) then it goes on with
complete lack of modularization, which was cleaned up later (cd68e161).
As usual, we don't consider the copyright of the stuff that has been
moved out cleanly.
There were also contributions to generic code by people who could not be
reached or who did not agree to the relicensing, but this was all
removed.
The only patches that we could not relicense and which were still in the
current code in some form are from Dénes Balatoni: 422b0d2a, 32937181.
We could not reach him, so commits f34e1a0d and 18905298 remove his
additions. It still leaves the demux_control() declaration itself, but
we don't consider it copyrightable. It's basically an idiom that existed
in MPlayer before that change, applied to the demuxer struct. (We even
went as far as making sure to remove all DEMUXER_CTRLs the original
author added.)
Commit be54f481 might be a bit of a corner case, but this was rewritten,
and we consider the old copyright removed long ago.
While we could easily ifdef-out this file for a LGPL core, it's still
annoying, and also the only GPL file remaining in player/ that is not
based on mplayer.c.
This file originates from subreader.c. It's not clear whether the
original author of it gave us permission to relicense to LGPL (he
probably did, but without further clarification it's sort of ambiguous),
but the subtitle file search code was written by other authors anyway
(see 7eef93819f).
One contribution (574eb892ea) is a bit of a corner case, as
test_ext_list() now does a bstrcasecmp(). But I don't think the
copyright remains here. (I asked the author anyway, just in case. But
I didn't wait for the answer.)
In some other cases, contributors who could not be reached added some
subtitle extensions. I don't think those are copyrightable on their own,
but I dropped them anyway just to be sure.
cehoyos adds the step_property command in 7a71da01d, and it could be
argued that copyright of this still applies to the later add/cycle
commands (a668ae0ff9). While I'm not sure if this is really the case,
stay conservative for now and mark these commands as GPL-only. Mark the
command.c code too, although that is not being relicensed yet.
I'm leaving the MP_CMD_* enum items, as they are obviously different.
In commit 116ca0c768, "veal" (essentially an anonymous author) adds an
"osd_show_property_text" command (well, the commit message says "based
on" that person's code, so it's not clear how much is from him or from
albeu, who agreed to LGPL). This was later merged again with the
"osd_show_text" command, and then all original code was removed in
commit 58cc0f637f, so I claim that no copyright applies anymore. (Though
technically the input.conf addition still might be copyrighted, so I'm
just dropping it to get rid of the thought.)
"kiriuja" added 2f376d1b39 (sub_load etc.) and be54f4813 (switch_audio).
The latter is gone. I would argue that the former is fully rewritten
with commits b7052b431c and 0f155921b0. But like in the step_property
case, I will be overly conservative for now, and mark them as GPL-only,
as this is potentially shaky and should be thought through first. (Not
bothering with the command define/enum in the header, as it will be
unused in LGPL mode anyway.)
keycodes.c/h can be GPL, except for commit 2b1f95dcc2, which is a
patch by someone who wasn't asked yet. Before doing something radical, I
will wait for a reply.
"Almost" because this might contain copyright by michael, who agreed
with LGPL, but only once the core is LGPL. This is preparation for that
to happen.
Apart from that, the usual remarks apply. In particular, dec_video.c
started out quite chaotic with no modularization, but was later
basically gutted, and in general rewritten a bunch of times. Not going
to give a history lesson.
Special attention needs to be given to 3 patches by cehosos, who did not
agree to the relicensing:
240b743ebdf: --field-dominance
e32cbbf7dc3: reinit VO if aspect ratio changes
306f6243fdf: use container aspect if codec aspect unset (?)
The first patch is pretty clearly still in the current code, and needs
to be disabled for LGPL.
The functionality of the second patch is still active, but implemented
completely different, and as part of general frame parameter changes (at
the time of the patch, MPlayer already reinitialized the VO on frame
size and pixel format changes - all this was merged into a single check
for changing image parameters).
The third patch makes me a bit more uncomfortable. It appears the code
was moved to dec_video.c in de68b8f23c, and further changed in
82f0d373, 0a0bb905, and bf13bd0d. You could claim that cehoyos'
copyright still sticks. Fortunately, we implement alternative aspect
detection, which is simpler and probably preferable, and which arguably
contains none of the original code and logic, and thus should be fully
safe.
While I don't know if cehoyos' copyright actually still applies, I'm
more comfortable with making the code GPL-only for now. Also change the
default to use the (in future) plain LGPL code, and deprecate the one
associated with the GPL code, so we can eventually remove the GPL code.
But it's also possible we decide that the copyright doesn't apply, and
undo the deprecation and GPL guards.
I expect that users won't notice anything. If you ask me, the old aspect
method was probably an accidental bug instead of intentional behavior.
Although, the new aspect method was broken too, so I had to fix it.
image_writer.c has code originating from vf_screenshot.c, vo_jpeg.c, and
potentially others. vo_image.c is based on a bunch of those VOs as well,
and the intention was to replace them with a single codebase.
vo_tga.c was written by someone who was not or not could be contacted,
but it doesn't matter anyway, as no code from that initial patch was
used.
One rather old patch (57f77bb41a) reordered by libjpeg patch API calls,
and the author of the patch was not contacted. But at least with the
smoothing_factor override removed, this pretty much exactly corresponds
to the official libjpeg API example (and might even reflect a change to
those - didn't dig deeper). This removes the -jpeg-smooth option. While
we're at it, remove all the other dropped jpeg options from the manpage
(which was forgotten in past changes).
The problem with fmt-conversion.h is that "lucabe", who disagreed with
LGPL, originally wrote it. But it was actually rewritten by "reimar"
later. The original switch statement was replaced with a lookup table.
No code other than the imgfmt2pixfmt() function signature survives.
Neither the format pairs (PIXFMT<->IMGFMT), nor the concept of mapping
them, can be copyrighted.
So changing the license should be fine, because reimar and all other
authors involved with the new code agreed to LGPL.
We also don't consider format pairs added later as copyrightable.
(The direct-mapping idea mentioned in the "Copyright" file seems
attractive, and I might implement in later anyway.)
Likewise, there might be some format names added to img_format.h, which
are not covered by relicensing agreements. These all affect "later"
additions, and they follow either the FFmpeg PIXFMT naming or some other
pre-existing logic, so this should be fine.
This file is an leftover from when img_format.h was changed from using
the ancient FourCCs (based on Microsoft multimedia conventions) for
pixel formats to a simple enum. The remaining cases still inherently
used FourCCs for whatever reasons.
Instead of worrying about residual copyrights in this file, just move it
into code we don't want to relicense (the ancient Linux TV code). We
have to fix some other code depending on it. For the most part, we just
replace the MP_FOURCC macro with libavutil's MKTAG (although the macro
definition is exactly the same). In demux_raw, we drop some pre-defined
FourCCs, but it's not like it matters. (Instead of
--demuxer-rawvideo-format use --demuxer-rawvideo-mp-format.)
It was an attempt to move some MPlayer filters (which were removed from
mpv) to external, loadable filters. That worked well, but then the
MPlayer filters were ported to libavfilter (independently), so they're
available again. Also there is a more widely supported and more advanced
loadable filter system supported by mpv: vapoursynth.
In conclusion, vf_dlopen is not useful anymore, confusing, and requires
quite a bit of code (and probably wouldn't survive the rewrite of the
mpv video filter chain, which has to come at some point). It has some
implicit dependencies on internal conventions, like possibly the format
names dropped in the previous commit.
We also deprecated it last release. Drop it.
nanahi
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