Based off the srt encoder. The following features are unimplemented:
- fonts, colors, sizes
- alignment and positioning
The rest works well. For example, use ffmpeg to convert subtitles into the .vtt format:
ffmpeg -i input.srt output.vtt
Signed-off-by: Aman Gupta <ffmpeg@tmm1.net>
Signed-off-by: Clément Bœsch <u@pkh.me>
with -f lavfi -i testsrc=s=hd1080 as source:
rotate=90*PI/180 vs transpose=clock: 42fps -> 64fps
rotate=180*PI/180 vs vflip,hflip: 75fps -> 77fps
rotate=270*PI/180 vs transpose=cclock: 43fps -> 63fps
Add AV_PKT_DATA_DISPLAYMATRIX and AV_FRAME_DATA_DISPLAYMATRIX as stream and
frame side data (respectively) to describe a display transformation matrix
for linear transformation operations on the decoded video.
Add functions to easily extract a rotation angle from a matrix and
conversely to setup a matrix for a given rotation angle.
Signed-off-by: Anton Khirnov <anton@khirnov.net>
Right now, the caller has to manually manage some allocated
AVCodecContext fields, like extradata or subtitle_header. This is
fragile and prone to leaks, especially if we want to add more such
fields in the future.
The only reason for this behaviour is so that the AVStream codec context
can be reused for decoding. Such reuse is discouraged anyway, so this
commit is the first step to deprecating it.
These functions are using the POSIX clock_gettime() function with the
CLOCK_MONOTONIC clock id. If these are not present on the targeted
platform, the new functions will fallback on using the original realtime functions
av_gettime() and av_usleep().
Monotonic support can be added on other platforms with their
equivalent native system API eventually if possible.
Whenever time is requested to measure relative time, the monotonic clock,
when available, is superior to the system realtime clock because it is
not affected by discontinuous jumps in the system time
In a future step, offering the flexibility to let the user choose between
rt and monotonic clock for avdevices packets will be investigated.
It is very easy to experience the issues that this patch attempt to address
by rewinding back in the past the system time while ffmpeg is running.
this is breaking the ffmpeg report printing (ffmepg.c:print_report()) and
the the rate emulator functionality (-re) without the patch.
Signed-off-by: Olivier Langlois <olivier@trillion01.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Describe the option added in commit f1c167496e
Signed-off-by: Olivier Langlois <olivier@trillion01.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Use it instead of checking CODEC_FLAG_BITEXACT in the first stream's
codec context.
Using codec options inside lavf is fragile and can easily break when the
muxing codec context is not the encoding context.
Existing av_opt_set_dict doesn't accept flags.
It doesn't allow to pass options to nested structs.
New function alllows that.
Signed-off-by: Lukasz Marek <lukasz.m.luki2@gmail.com>
Old Intel GPUs expect the reference frame index to the actual surface,
instead of the index into RefFrameList as specified by the spec.
This workaround should be set when using one of the "ClearVideo" decoder
devices.
Signed-off-by: Anton Khirnov <anton@khirnov.net>