Motivated by a desire to use vf_libplacebo as a GPU-accelerated
cropping/padding/zooming filter. This commit adds support for setting
the `input/target.crop` fields as dynamic expressions.
Re-use the same generic variables available to other scale and crop type
filters, and also add some more that we can afford as a result of being
able to set these properties dynamically.
It's worth pointing out that `out_t/ot` is currently redundant with
`in_t/t` since it will always contain the same PTS values, but I plan on
changing this in the near future.
I decided to also expose `crop_w/crop_h` and `pos_w/pos_h` as variables
in the expression parser itself, since this enables the fairly common
use case of determining dimensions first and then placing the image
appropriately, such as is done in the default behavior (which centers
the cropped/placed region by default).
In some circumstances, libplacebo will clear the background as a result
of cropping/padding. Currently, this uses the hard-coded default fill
color of black. This option makes this behavior configurable.
Will remove native backend, so change the default backend in filters,
and also remove the python scripts which generate native model file.
Signed-off-by: Ting Fu <ting.fu@intel.com>
Some testing revealed this to be a very efficient and reliable method of
ingesting GPU frames into libplacebo, so it's a good idea to give as an
example.
This example being first is now misleading because round-tripping
through hwdownload/hwupload is neither required nor recommended. Also,
the comment about avoiding format conversion is unnecessary because
`libplacebo` will now inherit the input frame format by default.
This option adds a long string of numbers to the progress line, where
i-th number contains the base-2 logarithm of the number of times a frame
with this QP value was seen by print_report().
There are multiple problems with this feature:
* despite this existing since 2005, web search shows no indication
that it was ever useful for any meaningful purpose;
* the format of what is printed is entirely undocumented, one has to
find it out from the source code;
* QP values above 31 are silently ignored;
* it only works with one video stream;
* as it relies on global state, it is in conflict with ongoing
architectural changes.
It then seems that the nontrivial cost of maintaining this option is not
worth its negligible (or possibly negative - since it pollutes the
already large option space) value.
Users who really need similar functionality can also implement it
themselves using -vstats.
The function now accepts an existing buffer to avoid unnecessary allocations,
as well as only reporting the needed amount of bytes if you pass a NULL pointer
as input for data.
For this, both parameters become input and output, as well as making data
optional. This is backwards compatible, and as such not breaking any existing
use of the function in external code (if there's any).
Signed-off-by: James Almer <jamrial@gmail.com>
In particular, add a sentence to introduce the example, and add a
simpler starting example with no options.
Also use different format for input.avi and output.mp4, to convey
that the conversion also works on the container format.
Address issue:
http://trac.ffmpeg.org/ticket/8730
Document metadata entries set by the filter, extend and clarify
options, add additional example showing how to extract the generated
data.
Address issue:
http://trac.ffmpeg.org/ticket/8766
Drop mention of unsupported N:M syntax, dropped since 0ed61546c4.
Also, drop reference of common expression constants, and fix
description of a expression parameter.
Fix issue:
http://trac.ffmpeg.org/ticket/9974
Reference drawtext textfile option and ffmpeg -filter_complex_script
and -filter_script as possible solutions to avoid shell escaping.
Address issue:
http://trac.ffmpeg.org/ticket/9008
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>
These fields are supposed to store information about the packet the
frame was decoded from, specifically the byte offset it was stored at
and its size.
However,
- the fields are highly ad-hoc - there is no strong reason why
specifically those (and not any other) packet properties should have a
dedicated field in AVFrame; unlike e.g. the timestamps, there is no
fundamental link between coded packet offset/size and decoded frames
- they only make sense for frames produced by decoding demuxed packets,
and even then it is not always the case that the encoded data was
stored in the file as a contiguous sequence of bytes (in order for pos
to be well-defined)
- pkt_pos was added without much explanation, apparently to allow
passthrough of this information through lavfi in order to handle byte
seeking in ffplay. That is now implemented using arbitrary user data
passthrough in AVFrame.opaque_ref.
- several filters use pkt_pos as a variable available to user-supplied
expressions, but there seems to be no established motivation for using them.
- pkt_size was added for use in ffprobe, but that too is now handled
without using this field. Additonally, the values of this field
produced by libavcodec are flawed, as described in the previous
ffprobe conversion commit.
In summary - these fields are ill-defined and insufficiently motivated,
so deprecate them.
Paul B Mahol
Davy Durham
Anton Khirnov
James Almer
Niklas Haas
Ting Fu
Marton Balint
Sil Vilerino
Thilo Borgmann
Stefano Sabatini
jackarain
TADANO Tokumei
Michael Niedermayer
Raphaël Zumer