For now, this API is supposed to replace all the internal uses
of reference counted objects in libavcodec; "internal" here
means that the object is created in libavcodec and is never
put directly in the hands of anyone outside of it.
It is intended to be made public eventually, but for now
I enjoy the ability to modify it freely.
Several shortcomings of the AVBuffer API motivated this API:
a) The unnecessary allocations (and ensuing error checks)
when using the API. Besides the need for runtime checks it
imposes upon the developer the burden of thinking through
what happens in case an error happens. Furthermore, these
error paths are typically not covered by FATE.
b) The AVBuffer API is designed with buffers and not with
objects in mind: The type for the actual buffers used
is uint8_t*; it pretends to be able to make buffers
writable, but this is wrong in case the buffer is not a POD.
Another instance of this thinking is the lack of a reset
callback in the AVBufferPool API.
c) The AVBuffer API incurs unnecessary indirections by
going through the AVBufferRef.data pointer. In case the user
tries to avoid this indirection and stores a pointer to
AVBuffer.data separately (which also allows to use the correct
type), the user has to keep these two pointers in sync
in case they can change (and in any case has two pointers
occupying space in the containing context). See the following
commit using this API for H.264 parameter sets for an example
of the removal of such syncing code as well as the casts
involved in the parts where only the AVBufferRef* pointer
was stored.
d) Given that the AVBuffer API allows custom allocators,
creating refcounted objects with dedicated free functions
often involves a lot of boilerplate like this:
obj = av_mallocz(sizeof(*obj));
ref = av_buffer_create((uint8_t*)obj, sizeof(*obj), free_func, opaque, 0);
if (!ref) {
av_free(obj);
return AVERROR(ENOMEM);
}
(There is also a corresponding av_free() at the end of free_func().)
This is now just
obj = ff_refstruct_alloc_ext(sizeof(*obj), 0, opaque, free_func);
if (!obj)
return AVERROR(ENOMEM);
See the subsequent patch for the framepool (i.e. get_buffer.c)
for an example.
This API does things differently; it is designed to be lightweight*
as well as geared to the common case where the allocator of the
underlying object does not matter as long as it is big enough and
suitably aligned. This allows to allocate the user data together
with the API's bookkeeping data which avoids an allocation as well
as the need for separate pointers to the user data and the API's
bookkeeping data. This entails that the actual allocation of the
object is performed by RefStruct, not the user. This is responsible
for avoiding the boilerplate code mentioned in d).
As a downside, custom allocators are not supported, but it will
become apparent in subsequent commits that there are enough
usecases to make it worthwhile.
Another advantage of this API is that one only needs to include
the relevant header if one uses the API and not when one includes
the header or some other component that uses it. This is because there
is no RefStruct type analog of AVBufferRef. This brings with it
one further downside: It is not apparent from the pointer itself
whether the underlying object is managed by the RefStruct API
or whether this pointer is a reference to it (or merely a pointer
to it).
Finally, this API supports const-qualified opaque pointees;
this will allow to avoid casting const away by the CBS code.
*: Basically the only exception to the you-only-pay-for-what-you-use
rule is that it always uses atomics for the refcount.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
They were replaced by TX from libavutil; the tremendous work
to get to this point (both creating TX as well as porting
the users of the components removed in this commit) was
completely performed by Lynne alone.
Removing the subsystems from configure may break some command lines,
because the --disable-fft etc. options are no longer recognized.
Co-authored-by: Lynne <dev@lynne.ee>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Add a full parser to libavcodec for AV_CODEC_ID_JPEGXL. It finds the
end of the stream in order to packetize the codec, and it looks at
the headers to set preliminary information like dimensions and pixel
format.
Note that much of this code is duplicated from avformat/jpegxl_probe.c,
but that code will be removed and call this instead in the next commit.
Signed-off-by: Leo Izen <leo.izen@gmail.com>
libavcodec/vulkan_video_codec_av1std.h currently does not pass
checkheaders: It is missing stdint.h and vulkan/vulkan_core.h.
The comment "This header is NOT YET generated from the Khronos Vulkan
XML API Registry." as well as the fact that it does not use our standard
inclusion guards makes the file appear as if it is to be treated
like a third-party header and not one of our own. This commit
therefore "fixes" the issue by unconditionally skipping said header.
Reviewed-by: Lynne <dev@lynne.ee>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Add CodedBitstreamContext to parse VPS,SPS,PPS in VVC nal units.
Implement parsing and writing of SPS,PPS,VPS,PH,AUD,SEI and slices.
Add ff_cbs_type_h266 to cbs types tables and AV_CODEC_ID_H266
to cbs codec ids.
Co-authored-by: Thomas Siedel <thomas.ff@spin-digital.com>
Signed-off-by: James Almer <jamrial@gmail.com>
* take num_ticks_per_picture_minus_1 into account, since that is a part
of the framerate computation
* stop exporting num_ticks_per_picture_minus_1 into
AVCodecContext.ticks_per_frame, as that field is used for other
purposes (in conjunction with repeat_pict, which is not used at all by
av1)
Avoid compiling error if included by multiple sources.
Signed-off-by: Jianhui Dai <jianhui.j.dai@intel.com>
Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>
This patch will add MPEG4 encoder using Android Mediacodec
Signed-off-by: Samuel Mira <samuel.mira@qt.io<mailto:samuel.mira@qt.io>>
Signed-off-by: Zhao Zhili <zhilizhao@tencent.com>
The only encoders avaliable using mediacodec were h264 and hevc. This
patch adds the vp9 encoder.
Signed-off-by: Samuel Mira <samuel.mira@qt.io<mailto:samuel.mira@qt.io>>
Signed-off-by: Zhao Zhili <zhilizhao@tencent.com>
This patch add another ARIB caption decoder using libaribcaption
external library.
Unlike libaribb24, it supports 3 types of subtitle outputs:
* text: plain text
* ass: ASS formatted text
* bitmap: bitmap image
Default subtitle type is ass as same as libaribb24.
Advantages compared with libaribb24 on ASS subtitle are:
* Subtitle positioning.
* Multi-rect subtitle: some captions are displayed at different
position at a time.
* More stability and reproducibility.
To compile with this feature:
* libaribcaption external library has to be pre-installed.
https://github.com/xqq/libaribcaption
* configure with `--enable-libaribcaption` option.
`--enable-libaribb24` and `--enable-libaribcaption` options are
not exclusive. If both enabled, libaribcaption precedes as
order listed in `libavcodec/allcodecs.c`.
Signed-off-by: rcombs <rcombs@rcombs.me>
Andreas Rheinhardt
Fei Wang
Paul B Mahol
Leo Izen
Thomas Siedel
Nuo Mi
Tomas Härdin
James Almer
Dawid Kozinski
Lynne
Samuel Mira
Anton Khirnov
Dai, Jianhui J
caleb
Michael Niedermayer
TADANO Tokumei
Raphaël Zumer
Dmitrii Ovchinnikov
Zhao Zhili