mpv/video/out/vo_sixel.c

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/*
* Sixel mpv output device implementation based on ffmpeg libavdevice implementation
* by Hayaki Saito
* https://github.com/saitoha/FFmpeg-SIXEL/blob/sixel/libavdevice/sixel.c
*
* Copyright (c) 2014 Hayaki Saito
*
* This file is part of mpv.
*
* mpv is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* mpv is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with mpv. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdio.h>
#include <stdlib.h>
#include <libswscale/swscale.h>
#include <sixel.h>
#include "config.h"
#include "options/m_config.h"
#include "osdep/terminal.h"
#include "sub/osd.h"
#include "vo.h"
#include "video/sws_utils.h"
#include "video/mp_image.h"
#if HAVE_POSIX
#include <unistd.h>
#endif
#define IMGFMT IMGFMT_RGB24
#define TERM_ESC_USE_GLOBAL_COLOR_REG "\033[?1070l"
#define TERMINAL_FALLBACK_COLS 80
#define TERMINAL_FALLBACK_ROWS 25
#define TERMINAL_FALLBACK_PX_WIDTH 320
#define TERMINAL_FALLBACK_PX_HEIGHT 240
struct vo_sixel_opts {
int diffuse;
int reqcolors;
bool fixedpal;
int threshold;
int width, height, top, left;
int pad_y, pad_x;
int rows, cols;
bool config_clear, alt_screen;
bool buffered;
};
struct priv {
// User specified options
struct vo_sixel_opts opts;
// Internal data
sixel_output_t *output;
sixel_dither_t *dither;
sixel_dither_t *testdither;
uint8_t *buffer;
char *sixel_output_buf;
bool skip_frame_draw;
int left, top; // image origin cell (1 based)
int width, height; // actual image px size - always reflects dst_rect.
int num_cols, num_rows; // terminal size in cells
int canvas_ok; // whether canvas vo->dwidth and vo->dheight are positive
int previous_histogram_colors;
struct mp_rect src_rect;
struct mp_rect dst_rect;
struct mp_osd_res osd;
struct mp_image *frame;
struct mp_sws_context *sws;
};
static const unsigned int depth = 3;
static int detect_scene_change(struct vo* vo)
{
struct priv* priv = vo->priv;
int previous_histogram_colors = priv->previous_histogram_colors;
int histogram_colors = 0;
// If threshold is set negative, then every frame must be a scene change
if (priv->dither == NULL || priv->opts.threshold < 0)
return 1;
histogram_colors = sixel_dither_get_num_of_histogram_colors(priv->testdither);
int color_difference_count = previous_histogram_colors - histogram_colors;
color_difference_count = (color_difference_count > 0) ? // abs value
color_difference_count : -color_difference_count;
if (100 * color_difference_count >
priv->opts.threshold * previous_histogram_colors)
{
priv->previous_histogram_colors = histogram_colors; // update history
return 1;
} else {
return 0;
}
}
static void dealloc_dithers_and_buffers(struct vo* vo)
{
struct priv* priv = vo->priv;
if (priv->buffer) {
talloc_free(priv->buffer);
priv->buffer = NULL;
}
if (priv->frame) {
talloc_free(priv->frame);
priv->frame = NULL;
}
if (priv->dither) {
sixel_dither_unref(priv->dither);
priv->dither = NULL;
}
if (priv->testdither) {
sixel_dither_unref(priv->testdither);
priv->testdither = NULL;
}
}
static SIXELSTATUS prepare_static_palette(struct vo* vo)
{
struct priv* priv = vo->priv;
if (!priv->dither) {
priv->dither = sixel_dither_get(BUILTIN_XTERM256);
if (priv->dither == NULL)
return SIXEL_FALSE;
sixel_dither_set_diffusion_type(priv->dither, priv->opts.diffuse);
}
sixel_dither_set_body_only(priv->dither, 0);
return SIXEL_OK;
}
static SIXELSTATUS prepare_dynamic_palette(struct vo *vo)
{
SIXELSTATUS status = SIXEL_FALSE;
struct priv *priv = vo->priv;
/* create histogram and construct color palette
* with median cut algorithm. */
status = sixel_dither_initialize(priv->testdither, priv->buffer,
priv->width, priv->height,
SIXEL_PIXELFORMAT_RGB888,
LARGE_NORM, REP_CENTER_BOX,
QUALITY_LOW);
if (SIXEL_FAILED(status))
return status;
if (detect_scene_change(vo)) {
if (priv->dither) {
sixel_dither_unref(priv->dither);
priv->dither = NULL;
}
priv->dither = priv->testdither;
status = sixel_dither_new(&priv->testdither, priv->opts.reqcolors, NULL);
if (SIXEL_FAILED(status))
return status;
sixel_dither_set_diffusion_type(priv->dither, priv->opts.diffuse);
} else {
if (priv->dither == NULL)
return SIXEL_FALSE;
}
sixel_dither_set_body_only(priv->dither, 0);
return status;
}
static void update_canvas_dimensions(struct vo *vo)
{
// this function sets the vo canvas size in pixels vo->dwidth, vo->dheight,
// and the number of rows and columns available in priv->num_rows/cols
struct priv *priv = vo->priv;
int num_rows = TERMINAL_FALLBACK_ROWS;
int num_cols = TERMINAL_FALLBACK_COLS;
int total_px_width = 0;
int total_px_height = 0;
terminal_get_size2(&num_rows, &num_cols, &total_px_width, &total_px_height);
// If the user has specified rows/cols use them for further calculations
num_rows = (priv->opts.rows > 0) ? priv->opts.rows : num_rows;
num_cols = (priv->opts.cols > 0) ? priv->opts.cols : num_cols;
// If the pad value is set in between 0 and width/2 - 1, then we
// subtract from the detected width. Otherwise, we assume that the width
// output must be a integer multiple of num_cols and accordingly set
// total_width to be an integer multiple of num_cols. So in case the padding
// added by terminal is less than the number of cells in that axis, then rounding
// down will take care of correcting the detected width and remove padding.
if (priv->opts.width > 0) {
// option - set by the user, hard truth
total_px_width = priv->opts.width;
} else {
if (total_px_width <= 0) {
// ioctl failed to read terminal width
total_px_width = TERMINAL_FALLBACK_PX_WIDTH;
} else {
if (priv->opts.pad_x >= 0 && priv->opts.pad_x < total_px_width / 2) {
// explicit padding set by the user
total_px_width -= (2 * priv->opts.pad_x);
} else {
// rounded "auto padding"
total_px_width = total_px_width / num_cols * num_cols;
}
}
}
if (priv->opts.height > 0) {
total_px_height = priv->opts.height;
} else {
if (total_px_height <= 0) {
total_px_height = TERMINAL_FALLBACK_PX_HEIGHT;
} else {
if (priv->opts.pad_y >= 0 && priv->opts.pad_y < total_px_height / 2) {
total_px_height -= (2 * priv->opts.pad_y);
} else {
total_px_height = total_px_height / num_rows * num_rows;
}
}
}
// use n-1 rows for height
// The last row can't be used for encoding image, because after sixel encode
// the terminal moves the cursor to next line below the image, causing the
// last line to be empty instead of displaying image data.
// TODO: Confirm if the output height must be a multiple of 6, if not, remove
// the / 6 * 6 part which is setting the height to be a multiple of 6.
vo->dheight = total_px_height * (num_rows - 1) / num_rows / 6 * 6;
vo->dwidth = total_px_width;
priv->num_rows = num_rows;
priv->num_cols = num_cols;
priv->canvas_ok = vo->dwidth > 0 && vo->dheight > 0;
}
static void set_sixel_output_parameters(struct vo *vo)
{
// This function sets output scaled size in priv->width, priv->height
// and the scaling rectangles in pixels priv->src_rect, priv->dst_rect
// as well as image positioning in cells priv->top, priv->left.
struct priv *priv = vo->priv;
vo_get_src_dst_rects(vo, &priv->src_rect, &priv->dst_rect, &priv->osd);
// priv->width and priv->height are the width and height of dst_rect
// and they are not changed anywhere else outside this function.
// It is the sixel image output dimension which is output by libsixel.
priv->width = priv->dst_rect.x1 - priv->dst_rect.x0;
priv->height = priv->dst_rect.y1 - priv->dst_rect.y0;
// top/left values must be greater than 1. If it is set, then
// the image will be rendered from there and no further centering is done.
priv->top = (priv->opts.top > 0) ? priv->opts.top :
priv->num_rows * priv->dst_rect.y0 / vo->dheight + 1;
priv->left = (priv->opts.left > 0) ? priv->opts.left :
priv->num_cols * priv->dst_rect.x0 / vo->dwidth + 1;
}
static int update_sixel_swscaler(struct vo *vo, struct mp_image_params *params)
{
struct priv *priv = vo->priv;
priv->sws->src = *params;
priv->sws->src.w = mp_rect_w(priv->src_rect);
priv->sws->src.h = mp_rect_h(priv->src_rect);
priv->sws->dst = (struct mp_image_params) {
.imgfmt = IMGFMT,
.w = priv->width,
.h = priv->height,
.p_w = 1,
.p_h = 1,
};
dealloc_dithers_and_buffers(vo);
priv->frame = mp_image_alloc(IMGFMT, priv->width, priv->height);
if (!priv->frame)
return -1;
if (mp_sws_reinit(priv->sws) < 0)
return -1;
// create testdither only if dynamic palette mode is set
if (!priv->opts.fixedpal) {
SIXELSTATUS status = sixel_dither_new(&priv->testdither,
priv->opts.reqcolors, NULL);
if (SIXEL_FAILED(status)) {
MP_ERR(vo, "update_sixel_swscaler: Failed to create new dither: %s\n",
sixel_helper_format_error(status));
return -1;
}
}
priv->buffer =
talloc_array(NULL, uint8_t, depth * priv->width * priv->height);
return 0;
}
static inline int sixel_buffer(char *data, int size, void *priv) {
char **out = (char **)priv;
*out = talloc_strndup_append_buffer(*out, data, size);
return size;
}
static inline int sixel_write(char *data, int size, void *priv)
{
FILE *p = (FILE *)priv;
// On POSIX platforms, write() is the fastest method. It also is the only
// one that allows atomic writes so mpvs output will not be interrupted
// by other processes or threads that write to stdout, which would cause
// screen corruption. POSIX does not guarantee atomicity for writes
// exceeding PIPE_BUF, but at least Linux does seem to implement it that
// way.
#if HAVE_POSIX
int remain = size;
while (remain > 0) {
ssize_t written = write(fileno(p), data, remain);
if (written < 0)
return written;
remain -= written;
data += written;
}
return size;
#else
int ret = fwrite(data, 1, size, p);
fflush(p);
return ret;
#endif
}
static inline void sixel_strwrite(char *s)
{
sixel_write(s, strlen(s), stdout);
}
static int reconfig(struct vo *vo, struct mp_image_params *params)
{
struct priv *priv = vo->priv;
int ret = 0;
update_canvas_dimensions(vo);
if (priv->canvas_ok) { // if too small - succeed but skip the rendering
set_sixel_output_parameters(vo);
ret = update_sixel_swscaler(vo, params);
}
if (priv->opts.config_clear)
sixel_strwrite(TERM_ESC_CLEAR_SCREEN);
vo->want_redraw = true;
return ret;
}
static void draw_frame(struct vo *vo, struct vo_frame *frame)
{
struct priv *priv = vo->priv;
SIXELSTATUS status;
struct mp_image *mpi = NULL;
int prev_rows = priv->num_rows;
int prev_cols = priv->num_cols;
int prev_height = vo->dheight;
int prev_width = vo->dwidth;
bool resized = false;
update_canvas_dimensions(vo);
if (!priv->canvas_ok)
return;
if (prev_rows != priv->num_rows || prev_cols != priv->num_cols ||
prev_width != vo->dwidth || prev_height != vo->dheight)
{
set_sixel_output_parameters(vo);
// Not checking for vo->config_ok because draw_frame is never called
// with a failed reconfig.
update_sixel_swscaler(vo, vo->params);
if (priv->opts.config_clear)
sixel_strwrite(TERM_ESC_CLEAR_SCREEN);
resized = true;
}
if (frame->repeat && !frame->redraw && !resized) {
// Frame is repeated, and no need to update OSD either
priv->skip_frame_draw = true;
return;
} else {
// Either frame is new, or OSD has to be redrawn
priv->skip_frame_draw = false;
}
// Normal case where we have to draw the frame and the image is not NULL
if (frame->current) {
mpi = mp_image_new_ref(frame->current);
struct mp_rect src_rc = priv->src_rect;
src_rc.x0 = MP_ALIGN_DOWN(src_rc.x0, mpi->fmt.align_x);
src_rc.y0 = MP_ALIGN_DOWN(src_rc.y0, mpi->fmt.align_y);
mp_image_crop_rc(mpi, src_rc);
// scale/pan to our dest rect
mp_sws_scale(priv->sws, priv->frame, mpi);
} else {
// Image is NULL, so need to clear image and draw OSD
mp_image_clear(priv->frame, 0, 0, priv->width, priv->height);
}
struct mp_osd_res dim = {
.w = priv->width,
.h = priv->height
};
osd_draw_on_image(vo->osd, dim, mpi ? mpi->pts : 0, 0, priv->frame);
// Copy from mpv to RGB format as required by libsixel
memcpy_pic(priv->buffer, priv->frame->planes[0], priv->width * depth,
priv->height, priv->width * depth, priv->frame->stride[0]);
// Even if either of these prepare palette functions fail, on re-running them
// they should try to re-initialize the dithers, so it shouldn't dereference
// any NULL pointers. flip_page also has a check to make sure dither is not
// NULL before drawing, so failure in these functions should still be okay.
if (priv->opts.fixedpal) {
status = prepare_static_palette(vo);
} else {
status = prepare_dynamic_palette(vo);
}
if (SIXEL_FAILED(status)) {
MP_WARN(vo, "draw_frame: prepare_palette returned error: %s\n",
sixel_helper_format_error(status));
}
if (mpi)
talloc_free(mpi);
}
static void flip_page(struct vo *vo)
{
struct priv* priv = vo->priv;
if (!priv->canvas_ok)
return;
// If frame is repeated and no update required, then we skip encoding
if (priv->skip_frame_draw)
return;
// Make sure that image and dither are valid before drawing
if (priv->buffer == NULL || priv->dither == NULL)
return;
// Go to the offset row and column, then display the image
priv->sixel_output_buf = talloc_asprintf(NULL, TERM_ESC_GOTO_YX,
priv->top, priv->left);
if (!priv->opts.buffered)
sixel_strwrite(priv->sixel_output_buf);
sixel_encode(priv->buffer, priv->width, priv->height,
depth, priv->dither, priv->output);
if (priv->opts.buffered)
sixel_write(priv->sixel_output_buf,
ta_get_size(priv->sixel_output_buf), stdout);
talloc_free(priv->sixel_output_buf);
}
static int preinit(struct vo *vo)
{
struct priv *priv = vo->priv;
SIXELSTATUS status = SIXEL_FALSE;
// Parse opts set by CLI or conf
priv->sws = mp_sws_alloc(vo);
priv->sws->log = vo->log;
mp_sws_enable_cmdline_opts(priv->sws, vo->global);
if (priv->opts.buffered)
status = sixel_output_new(&priv->output, sixel_buffer,
&priv->sixel_output_buf, NULL);
else
status = sixel_output_new(&priv->output, sixel_write, stdout, NULL);
if (SIXEL_FAILED(status)) {
MP_ERR(vo, "preinit: Failed to create output file: %s\n",
sixel_helper_format_error(status));
return -1;
}
sixel_output_set_encode_policy(priv->output, SIXEL_ENCODEPOLICY_FAST);
if (priv->opts.alt_screen)
sixel_strwrite(TERM_ESC_ALT_SCREEN);
sixel_strwrite(TERM_ESC_HIDE_CURSOR);
/* don't use private color registers for each frame. */
sixel_strwrite(TERM_ESC_USE_GLOBAL_COLOR_REG);
priv->dither = NULL;
// create testdither only if dynamic palette mode is set
if (!priv->opts.fixedpal) {
status = sixel_dither_new(&priv->testdither, priv->opts.reqcolors, NULL);
if (SIXEL_FAILED(status)) {
MP_ERR(vo, "preinit: Failed to create new dither: %s\n",
sixel_helper_format_error(status));
return -1;
}
}
priv->previous_histogram_colors = 0;
return 0;
}
static int query_format(struct vo *vo, int format)
{
return format == IMGFMT;
}
static int control(struct vo *vo, uint32_t request, void *data)
{
if (request == VOCTRL_SET_PANSCAN)
return (vo->config_ok && !reconfig(vo, vo->params)) ? VO_TRUE : VO_FALSE;
return VO_NOTIMPL;
}
static void uninit(struct vo *vo)
{
struct priv *priv = vo->priv;
sixel_strwrite(TERM_ESC_RESTORE_CURSOR);
if (priv->opts.alt_screen)
sixel_strwrite(TERM_ESC_NORMAL_SCREEN);
fflush(stdout);
if (priv->output) {
sixel_output_unref(priv->output);
priv->output = NULL;
}
dealloc_dithers_and_buffers(vo);
}
#define OPT_BASE_STRUCT struct priv
const struct vo_driver video_out_sixel = {
.name = "sixel",
.description = "terminal graphics using sixels",
.preinit = preinit,
.query_format = query_format,
.reconfig = reconfig,
.control = control,
.draw_frame = draw_frame,
.flip_page = flip_page,
.uninit = uninit,
.priv_size = sizeof(struct priv),
.priv_defaults = &(const struct priv) {
.opts.diffuse = DIFFUSE_AUTO,
.opts.reqcolors = 256,
.opts.threshold = -1,
.opts.fixedpal = true,
.opts.pad_y = -1,
.opts.pad_x = -1,
.opts.config_clear = true,
.opts.alt_screen = true,
},
.options = (const m_option_t[]) {
{"dither", OPT_CHOICE(opts.diffuse,
{"auto", DIFFUSE_AUTO},
{"none", DIFFUSE_NONE},
{"atkinson", DIFFUSE_ATKINSON},
{"fs", DIFFUSE_FS},
{"jajuni", DIFFUSE_JAJUNI},
{"stucki", DIFFUSE_STUCKI},
{"burkes", DIFFUSE_BURKES},
{"arithmetic", DIFFUSE_A_DITHER},
{"xor", DIFFUSE_X_DITHER})},
{"width", OPT_INT(opts.width)},
{"height", OPT_INT(opts.height)},
{"reqcolors", OPT_INT(opts.reqcolors)},
{"fixedpalette", OPT_BOOL(opts.fixedpal)},
{"threshold", OPT_INT(opts.threshold)},
{"top", OPT_INT(opts.top)},
{"left", OPT_INT(opts.left)},
{"pad-y", OPT_INT(opts.pad_y)},
{"pad-x", OPT_INT(opts.pad_x)},
{"rows", OPT_INT(opts.rows)},
{"cols", OPT_INT(opts.cols)},
{"config-clear", OPT_BOOL(opts.config_clear), },
{"exit-clear", OPT_BOOL(opts.alt_screen),
.deprecation_message = "replaced by --vo-sixel-alt-screen"},
{"alt-screen", OPT_BOOL(opts.alt_screen), },
{"buffered", OPT_BOOL(opts.buffered), },
{0}
},
.options_prefix = "vo-sixel",
};