c784820454 introduced a bool option type
as a replacement for the flag type, but didn't actually transition and
remove the flag type because it would have been too much mundane work.
Our canvas size calculation is affected by few factors, and rounded
down more than once - which can result in 0 width or (more typically)
height - e.g. when terminal height is one row.
If the width or height are 0 then all bets are off, so simply skip
the setups and rendering on this case. We can still recover
automatically if the terminal is resized to become bigger.
The obvious approach would be SIGWINCH, however, integrating it would
be tricky, so instead we simply poll the size on draw_frame.
This means the image won't resize automatically when still - e.g.
cover art or when paused, though it would re-fit on OSD changes.
The reference is allocated at reconfig and happens at least once (and
leaked at least once), but can also be called more, e.g. on zoom or
pan-and-scan changes.
testdither was being created irrespective of whether
opt_fixedpal is set or not. In case of opt_fixedpal=1,
testdither is not used in the `prepare_static_palette`
code. Hence only initialize it when opt_fixedpal is 0.
In sixel_dither_initialize, replace 3 with the libsixel
SIXEL_PIXELFORMAT_RGB888. Also in sixel_encode, the 4th
parameter is supposed to be depth, which also happens
to be the value of PIXELFORMAT_RGB888, so replacing that
constant with the depth value.
For two reasons:
1. It was counter intuitive that there's an "auto" value (which is
actually a libsixel value and not an mpv one), but it's not the
default value - our default was Atkinson.
2. "auto" provides better dithering than Atkinson with libsixel, which
is especially noticeable with smooth gradients - where Atkinson has
visible banding.
In libsixel 1.8.2 the "auto" value maps to Atkinson if the output
palette has up to 16 colors, or to Floyd-Steinberg otherwise (e.g.
using fixed palette with 256 colors chooses Floyd-Steinberg).
The issue was that we only uploaded the palette to the terminal when it
changed (once on init with fixed palette, every frame with dynamic
palette with trheshold=-1, only on scene change with threshold >= 0).
Now we upload it on every frame, and it seems to fix the mlterm image
corruption both with fixed palette and also with dynamic palette with
threshold (i.e. at frames which did not upload a palette).
It's not entirely clear why it's required with mlterm.
It would seem that the palette which libsixel uses with fixed palette
matches the built in default palette in xterm, but not in mlterm.
With dynamic palette we can guess that mlterm resets the palette after a
sixel image, but that's not confirmed.
Uploading the palette on every frame doesn't seem to slow down xterm
when using fixed palette - not clear yet why uploading a different
palette (when using fixedpalette=no) slows it down while same palette
on every frame doesn't.
In mlterm there's no slowdown either way - and now also no corruption.
By default we still clear the screen, but now it's possible to leave the
last sixel image on screen.
Allows mpv to be used as img2sixel of sorts, but with our auto-fit and
various mpv scaling/filters etc.
Currently in mpv functions sixel failures return the
value status which is of type SIXELSTATUS. So changing
it to -1 which is explicit and compatible with mpv.
Also log the errors using MP_ERR/MP_LOG with the
error string returned by libsixel to have more info.
fixedpalette seems to be slightly faster than dynamic
palette, and also in mlterm it avoids corruption of
too bright values overflowing to black. Hence setting
it to be default choice instead of dynamic palette.
Resize the image based on the dimensions reported by
vo_get_src_dst_rects to correctly handle aspect ratio
that might be set/ignored.
Added pad-x and pad-y options for padding.
These options will be used to remove the extra padding.
Some terminals report the padding of 2px in the ioctl
dimensions which can't be used for displaying sixel
output. These options can be used for fine tuning
the output video resolution.
Now all the terminal size detection and calculation logic
is done in a single function at resize. Also top and left
values are computed from the dst_rect parameters to simplify
the logic for the aspect ratio based centering.
Additionally vo-sixel-rows and vo-sixel-cols options
have been added to enable the user to override the values
in case of failures with get_terminal_size2.
This commit also adds ability to handle video zoom correctly.
Whenever video-zoom is triggered, the src and dst rects
will be updated. Scaling seems to work well now.
This has no changes to mpv sixel playback behaviour.
This is required because currently the offset values
and the resolutions are being overwritten and not
remembered.
Based on the implementation of ffmpeg's sixel backend output written
by Hayaki Saito
https://github.com/saitoha/FFmpeg-SIXEL/blob/sixel/libavdevice/sixel.c
Sixel is a protocol to display graphics in a terminal. This commit
adds support to play videos on a sixel enabled terminal using libsixel.
With --vo=sixel, the output will be in sixel format.
The input frame will be scaled to the user specified resolution
(--vo-sixel-width and --vo-sixel-height) using swscaler and then
encoded using libsixel and output to the terminal. This method
requires high cpu and there are high frame drops for 720p and
higher resolution videos and might require using lesser colors and
have drop in quality. Docs have all the supported options listed
to fine tune the output quality.
TODO: A few parameters of libsixel such as the sixel_encode_policy
and the SIXEL_XTERM16 variables are hardcoded, might want to
expose them as command line options. Also the initialization
resolution is not automatic and if the user doesn't specify the
dimensions, it picks 320x240 as the default resolution which is not
optimal. So need to automatically pick the best fit resolution for
the current open terminal window size.
Christoph Heinrich