Bring it up to date with current practice, as the current text does not
cover everything. Drop the reference to unprefixed exported symbols,
which do not exist anymore.
It describes a general development policy, not code formatting. It is
also not true, as these days we tend to prioritize correctness, safety,
and completeness over code size.
It is currently very out of touch with reality.
* declare we are using C99 fully, rather than C90 plus extensions
* mention our use of stdatomic.h
* mention forbidden C99 features, like VLAs and complex numbers
VP6 alpha in EA format is a second VP6 encoded video stream where only the Y
component is used and is interpreted as the alpha channel of the first VP6
stream. The alpha VP6 stream is muxed separately from the main VP6 stream, has
its own stream headers and packet headers. In theory the two streams might not
even have the same resolution (although most likely that is not something that
is seen or supported in the wild), but the format is capable of doing it.
Merged VP6 alpha (also known as the VP6A codec) means that a packet of the
video stream contains the corresponding packet of both VP6 substreams like
this:
{OffsetOfAlpha, DataPacket, AlphaDataPacket}
So data and alpha data of a frame is merged to a single packet, this is how VP6
video with alpha is muxed in FLV and SWF.
The first approach is more like how the demuxer sees data in the EA format,
unfortunately it is different to what the FLV or SWF format expects, so -
having no better place for it in the framework - I decided to do an optional
format conversion in the EA demuxer.
Signed-off-by: Marton Balint <cus@passwd.hu>
Add qsv_transcode example which shows how to use qsv to do hardware
accelerated transcoding, also show how to dynamically set encoding
parameters.
examples:
Normal usage:
qsv_transcode input.mp4 h264_qsv output.mp4 "g 60"
Dynamic setting usage:
qsv_transcode input.mp4 hevc_qsv output.mp4 "g 60 asyne_depth 1"
100 "g 120"
This command initializes codec with gop_size 60 and change it to
120 after 100 frames
Signed-off-by: Wenbin Chen <wenbin.chen@intel.com>
Signed-off-by: Haihao Xiang <haihao.xiang@intel.com>
As a result of a typo in the source code, this option was completely
non-functional. In order to fix it, without breaking the current default
behavior, explicitly change this default to 0.
This behavior is also consistent with how other scale filters behave by
default, so it's probably best to enshrine it anyways.
Drop the reference to directly committing code, because
- it is highly discouraged and very rarely done these days
- there is no good reason NOT to submit patches for review
Add a link to the development policy chapter.
Add skip_frame support to qsvenc. Use per-frame metadata
"qsv_skip_frame" to control it. skip_frame option defines the behavior
of qsv_skip_frame.
no_skip: Frame skipping is disabled.
insert_dummy: Encoder inserts into bitstream frame where all macroblocks
are encoded as skipped.
insert_nothing: Similar to insert_dummy, but encoder inserts nothing.
The skipped frames are still used in brc. For example, gop still include
skipped frames, and the frames after skipped frames will be larger in
size.
brc_only: skip_frame metadata indicates the number of missed frames
before the current frame.
Signed-off-by: Wenbin Chen <wenbin.chen@intel.com>
There are sill many users of these APIs within libav*, so this commit
introduced too many deprecation warnings, making compilation too noisy and
potentially hiding legit warnings.
Once the remaining users are ported, this can be reapplied.
This reverts commit 76d0038579.
This is a more explicit iteration API rather than using the "magic"
av_dict_get(d, "", t, AV_DICT_IGNORE_SUFFIX) which is not really
trivial to grasp what it does when casually reading through code.
Signed-off-by: Anton Khirnov <anton@khirnov.net>
summary: This patch modifies the `curves` filter with new `interp` option
to let user pick the existing natural cubic spline interpolation
and the new PCHIP interapolation.
reason: The natural cubic spline does not impose monotonicity between
the keypoints. As such, the fitted curve may vary wildly against
user's intension. The PCHIP interpolation is not as smooth as
the natural spline but guarantees the monotonicity. Providing
both options enhances users experience (e.g., reduces the number
of keypoints to realize the desired curve). See the related bug
report for the example of an ill-interpolated curve.
alternate solution:
Both Photoshop and GIMP appear to use monotonic interpolation in
their curve tools, which were the models for this filter. As
such, an alternate solution is to drop the natural spline and
go without the `interp` option.
related bug report: https://trac.ffmpeg.org/ticket/9947 (filed by myself)
Signed-off-by: Takeshi (Kesh) Ikuma <tikuma@hotmail.com>
This enables overriding the rotation as well as horizontal/vertical
flip state of a specific video stream on the input side.
Additionally, switch the singular test that was utilizing the rotation
metadata to instead override the input display rotation, thus leading
to the same result.
The FF_PAD_STRUCTURE is too complex for doxygen to be able to
properly handle, resulting in completely broken AVBPrint documentation.
To fix that, tell Doxygen what to expand that macro to.
