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mpv/sub/sd_lavc.c
wm4 27c5550de2 sd_lavc: implement --sub-pos for bitmap subtitles
Simple enough to do. May have mixed results. Typically, bitmap subtitles
will have a tight bounding box around the rendered text. But if for
example there is text on the top and bottom, it may be a single big
bitmap with a large transparent area between top and bottom. In
particular, DVD subtitles are really just a single screen-sized
RLE-encoded bitmap, though libavcodec will crop off transparent areas.

Like with sd_ass, you can't move subtitles _down_ if they are already in
their origin position. This could probably be improved, but I don't want
to deal with that right now.
2019-09-19 20:37:04 +02:00

614 lines
18 KiB
C

/*
* 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 <stdlib.h>
#include <assert.h>
#include <math.h>
#include <libavcodec/avcodec.h>
#include <libavutil/common.h>
#include <libavutil/intreadwrite.h>
#include <libavutil/opt.h>
#include "config.h"
#include "mpv_talloc.h"
#include "common/msg.h"
#include "common/av_common.h"
#include "demux/stheader.h"
#include "options/options.h"
#include "video/mp_image.h"
#include "video/out/bitmap_packer.h"
#include "img_convert.h"
#include "sd.h"
#include "dec_sub.h"
#define MAX_QUEUE 4
struct sub {
bool valid;
AVSubtitle avsub;
struct sub_bitmap *inbitmaps;
int count;
struct mp_image *data;
int bound_w, bound_h;
int src_w, src_h;
double pts;
double endpts;
int64_t id;
};
struct seekpoint {
double pts;
double endpts;
};
struct sd_lavc_priv {
AVCodecContext *avctx;
AVRational pkt_timebase;
struct sub subs[MAX_QUEUE]; // most recent event first
struct sub_bitmap *outbitmaps;
int64_t displayed_id;
int64_t new_id;
struct mp_image_params video_params;
double current_pts;
struct seekpoint *seekpoints;
int num_seekpoints;
struct bitmap_packer *packer;
};
static int init(struct sd *sd)
{
enum AVCodecID cid = mp_codec_to_av_codec_id(sd->codec->codec);
// Supported codecs must be known to decode to paletted bitmaps
switch (cid) {
case AV_CODEC_ID_DVB_SUBTITLE:
#if LIBAVCODEC_VERSION_MICRO >= 100
case AV_CODEC_ID_DVB_TELETEXT:
#endif
case AV_CODEC_ID_HDMV_PGS_SUBTITLE:
case AV_CODEC_ID_XSUB:
case AV_CODEC_ID_DVD_SUBTITLE:
break;
default:
return -1;
}
struct sd_lavc_priv *priv = talloc_zero(NULL, struct sd_lavc_priv);
AVCodecContext *ctx = NULL;
AVCodec *sub_codec = avcodec_find_decoder(cid);
if (!sub_codec)
goto error;
ctx = avcodec_alloc_context3(sub_codec);
if (!ctx)
goto error;
mp_lavc_set_extradata(ctx, sd->codec->extradata, sd->codec->extradata_size);
priv->pkt_timebase = mp_get_codec_timebase(sd->codec);
#if LIBAVCODEC_VERSION_MICRO >= 100
ctx->pkt_timebase = priv->pkt_timebase;
#endif
if (avcodec_open2(ctx, sub_codec, NULL) < 0)
goto error;
priv->avctx = ctx;
sd->priv = priv;
priv->displayed_id = -1;
priv->current_pts = MP_NOPTS_VALUE;
priv->packer = talloc_zero(priv, struct bitmap_packer);
return 0;
error:
MP_FATAL(sd, "Could not open libavcodec subtitle decoder\n");
avcodec_free_context(&ctx);
talloc_free(priv);
return -1;
}
static void clear_sub(struct sub *sub)
{
sub->count = 0;
sub->pts = MP_NOPTS_VALUE;
sub->endpts = MP_NOPTS_VALUE;
if (sub->valid)
avsubtitle_free(&sub->avsub);
sub->valid = false;
}
static void alloc_sub(struct sd_lavc_priv *priv)
{
clear_sub(&priv->subs[MAX_QUEUE - 1]);
struct sub tmp = priv->subs[MAX_QUEUE - 1];
for (int n = MAX_QUEUE - 1; n > 0; n--)
priv->subs[n] = priv->subs[n - 1];
priv->subs[0] = tmp;
// clear only some fields; the memory allocs can be reused
priv->subs[0].valid = false;
priv->subs[0].count = 0;
priv->subs[0].src_w = 0;
priv->subs[0].src_h = 0;
priv->subs[0].id = priv->new_id++;
}
static void convert_pal(uint32_t *colors, size_t count, bool gray)
{
for (int n = 0; n < count; n++) {
uint32_t c = colors[n];
uint32_t b = c & 0xFF;
uint32_t g = (c >> 8) & 0xFF;
uint32_t r = (c >> 16) & 0xFF;
uint32_t a = (c >> 24) & 0xFF;
if (gray)
r = g = b = (r + g + b) / 3;
// from straight to pre-multiplied alpha
b = b * a / 255;
g = g * a / 255;
r = r * a / 255;
colors[n] = b | (g << 8) | (r << 16) | (a << 24);
}
}
// Initialize sub from sub->avsub.
static void read_sub_bitmaps(struct sd *sd, struct sub *sub)
{
struct mp_subtitle_opts *opts = sd->opts;
struct sd_lavc_priv *priv = sd->priv;
AVSubtitle *avsub = &sub->avsub;
MP_TARRAY_GROW(priv, sub->inbitmaps, avsub->num_rects);
packer_set_size(priv->packer, avsub->num_rects);
// If we blur, we want a transparent region around the bitmap data to
// avoid "cut off" artifacts on the borders.
bool apply_blur = opts->sub_gauss != 0.0f;
int extend = apply_blur ? 5 : 0;
// Assume consumers may use bilinear scaling on it (2x2 filter)
int padding = 1 + extend;
priv->packer->padding = padding;
// For the sake of libswscale, which in some cases takes sub-rects as
// source images, and wants 16 byte start pointer and stride alignment.
int align = 4;
for (int i = 0; i < avsub->num_rects; i++) {
struct AVSubtitleRect *r = avsub->rects[i];
struct sub_bitmap *b = &sub->inbitmaps[sub->count];
if (r->type != SUBTITLE_BITMAP) {
MP_ERR(sd, "unsupported subtitle type from libavcodec\n");
continue;
}
if (!(r->flags & AV_SUBTITLE_FLAG_FORCED) && opts->forced_subs_only)
continue;
if (r->w <= 0 || r->h <= 0)
continue;
b->bitmap = r; // save for later (dumb hack to avoid more complexity)
priv->packer->in[sub->count] = (struct pos){r->w + (align - 1), r->h};
sub->count++;
}
priv->packer->count = sub->count;
if (packer_pack(priv->packer) < 0) {
MP_ERR(sd, "Unable to pack subtitle bitmaps.\n");
sub->count = 0;
}
if (!sub->count)
return;
struct pos bb[2];
packer_get_bb(priv->packer, bb);
sub->bound_w = bb[1].x;
sub->bound_h = bb[1].y;
if (!sub->data || sub->data->w < sub->bound_w || sub->data->h < sub->bound_h) {
talloc_free(sub->data);
sub->data = mp_image_alloc(IMGFMT_BGRA, priv->packer->w, priv->packer->h);
if (!sub->data) {
sub->count = 0;
return;
}
talloc_steal(priv, sub->data);
}
for (int i = 0; i < sub->count; i++) {
struct sub_bitmap *b = &sub->inbitmaps[i];
struct pos pos = priv->packer->result[i];
struct AVSubtitleRect *r = b->bitmap;
uint8_t **data = r->data;
int *linesize = r->linesize;
b->w = r->w;
b->h = r->h;
b->x = r->x;
b->y = r->y;
// Choose such that the extended start position is aligned.
pos.x = MP_ALIGN_UP(pos.x - extend, align) + extend;
b->src_x = pos.x;
b->src_y = pos.y;
b->stride = sub->data->stride[0];
b->bitmap = sub->data->planes[0] + pos.y * b->stride + pos.x * 4;
sub->src_w = FFMAX(sub->src_w, b->x + b->w);
sub->src_h = FFMAX(sub->src_h, b->y + b->h);
assert(r->nb_colors > 0);
assert(r->nb_colors <= 256);
uint32_t pal[256] = {0};
memcpy(pal, data[1], r->nb_colors * 4);
convert_pal(pal, 256, opts->sub_gray);
for (int y = -padding; y < b->h + padding; y++) {
uint32_t *out = (uint32_t*)((char*)b->bitmap + y * b->stride);
int start = 0;
for (int x = -padding; x < 0; x++)
out[x] = 0;
if (y >= 0 && y < b->h) {
uint8_t *in = data[0] + y * linesize[0];
for (int x = 0; x < b->w; x++)
*out++ = pal[*in++];
start = b->w;
}
for (int x = start; x < b->w + padding; x++)
*out++ = 0;
}
b->bitmap = (char*)b->bitmap - extend * b->stride - extend * 4;
b->src_x -= extend;
b->src_y -= extend;
b->x -= extend;
b->y -= extend;
b->w += extend * 2;
b->h += extend * 2;
if (apply_blur)
mp_blur_rgba_sub_bitmap(b, opts->sub_gauss);
}
}
static void decode(struct sd *sd, struct demux_packet *packet)
{
struct mp_subtitle_opts *opts = sd->opts;
struct sd_lavc_priv *priv = sd->priv;
AVCodecContext *ctx = priv->avctx;
double pts = packet->pts;
double endpts = MP_NOPTS_VALUE;
double duration = packet->duration;
AVSubtitle sub;
AVPacket pkt;
// libavformat sets duration==0, even if the duration is unknown. Some files
// also have actually subtitle packets with duration explicitly set to 0
// (yes, at least some of such mkv files were muxed by libavformat).
// Assume there are no bitmap subs that actually use duration==0 for
// hidden subtitle events.
if (duration == 0)
duration = -1;
if (pts == MP_NOPTS_VALUE)
MP_WARN(sd, "Subtitle with unknown start time.\n");
mp_set_av_packet(&pkt, packet, &priv->pkt_timebase);
if (ctx->codec_id == AV_CODEC_ID_DVB_TELETEXT) {
char page[4];
snprintf(page, sizeof(page), "%d", opts->teletext_page);
av_opt_set(ctx, "txt_page", page, AV_OPT_SEARCH_CHILDREN);
}
int got_sub;
int res = avcodec_decode_subtitle2(ctx, &sub, &got_sub, &pkt);
if (res < 0 || !got_sub)
return;
if (sub.pts != AV_NOPTS_VALUE)
pts = sub.pts / (double)AV_TIME_BASE;
if (pts != MP_NOPTS_VALUE) {
if (sub.end_display_time > sub.start_display_time &&
sub.end_display_time != UINT32_MAX)
{
duration = (sub.end_display_time - sub.start_display_time) / 1000.0;
}
pts += sub.start_display_time / 1000.0;
if (duration >= 0)
endpts = pts + duration;
// set end time of previous sub
struct sub *prev = &priv->subs[0];
if (prev->valid) {
if (prev->endpts == MP_NOPTS_VALUE || prev->endpts > pts)
prev->endpts = pts;
if (opts->sub_fix_timing && pts - prev->endpts <= SUB_GAP_THRESHOLD)
prev->endpts = pts;
for (int n = 0; n < priv->num_seekpoints; n++) {
if (priv->seekpoints[n].pts == prev->pts) {
priv->seekpoints[n].endpts = prev->endpts;
break;
}
}
}
// This subtitle packet only signals the end of subtitle display.
if (!sub.num_rects) {
avsubtitle_free(&sub);
return;
}
}
alloc_sub(priv);
struct sub *current = &priv->subs[0];
current->valid = true;
current->pts = pts;
current->endpts = endpts;
current->avsub = sub;
read_sub_bitmaps(sd, current);
if (pts != MP_NOPTS_VALUE) {
for (int n = 0; n < priv->num_seekpoints; n++) {
if (priv->seekpoints[n].pts == pts)
goto skip;
}
// Set arbitrary limit as safe-guard against insane files.
if (priv->num_seekpoints >= 10000)
MP_TARRAY_REMOVE_AT(priv->seekpoints, priv->num_seekpoints, 0);
MP_TARRAY_APPEND(priv, priv->seekpoints, priv->num_seekpoints,
(struct seekpoint){.pts = pts, .endpts = endpts});
skip: ;
}
}
static void get_bitmaps(struct sd *sd, struct mp_osd_res d, int format,
double pts, struct sub_bitmaps *res)
{
struct sd_lavc_priv *priv = sd->priv;
struct mp_subtitle_opts *opts = sd->opts;
priv->current_pts = pts;
struct sub *current = NULL;
for (int n = 0; n < MAX_QUEUE; n++) {
struct sub *sub = &priv->subs[n];
if (!sub->valid)
continue;
if (pts == MP_NOPTS_VALUE ||
((sub->pts == MP_NOPTS_VALUE || pts >= sub->pts) &&
(sub->endpts == MP_NOPTS_VALUE || pts < sub->endpts)))
{
// Ignore "trailing" subtitles with unknown length after 1 minute.
if (sub->endpts == MP_NOPTS_VALUE && pts >= sub->pts + 60)
break;
current = sub;
break;
}
}
if (!current)
return;
MP_TARRAY_GROW(priv, priv->outbitmaps, current->count);
for (int n = 0; n < current->count; n++)
priv->outbitmaps[n] = current->inbitmaps[n];
res->parts = priv->outbitmaps;
res->num_parts = current->count;
if (priv->displayed_id != current->id)
res->change_id++;
priv->displayed_id = current->id;
res->packed = current->data;
res->packed_w = current->bound_w;
res->packed_h = current->bound_h;
res->format = SUBBITMAP_RGBA;
double video_par = 0;
if (priv->avctx->codec_id == AV_CODEC_ID_DVD_SUBTITLE &&
opts->stretch_dvd_subs)
{
// For DVD subs, try to keep the subtitle PAR at display PAR.
double par = priv->video_params.p_w / (double)priv->video_params.p_h;
if (isnormal(par))
video_par = par;
}
if (priv->avctx->codec_id == AV_CODEC_ID_HDMV_PGS_SUBTITLE)
video_par = -1;
if (opts->stretch_image_subs)
d.ml = d.mr = d.mt = d.mb = 0;
int w = priv->avctx->width;
int h = priv->avctx->height;
if (w <= 0 || h <= 0 || opts->image_subs_video_res) {
w = priv->video_params.w;
h = priv->video_params.h;
}
if (current->src_w > w || current->src_h > h) {
w = priv->video_params.w;
h = priv->video_params.h;
}
if (opts->sub_pos != 100 && opts->ass_style_override) {
int offset = (100 - opts->sub_pos) / 100.0 * h;
for (int n = 0; n < res->num_parts; n++) {
struct sub_bitmap *sub = &res->parts[n];
// Decide by heuristic whether this is a sub-title or something
// else (top-title, covering whole screen).
if (sub->y < h / 2)
continue;
// Allow moving up the subtitle, but only until it clips.
sub->y = MPMAX(sub->y - offset, 0);
}
}
osd_rescale_bitmaps(res, w, h, d, video_par);
}
static bool accepts_packet(struct sd *sd, double min_pts)
{
struct sd_lavc_priv *priv = sd->priv;
double pts = priv->current_pts;
if (min_pts != MP_NOPTS_VALUE) {
// guard against bogus rendering PTS in the future.
if (pts == MP_NOPTS_VALUE || min_pts < pts)
pts = min_pts;
// Heuristic: we assume rendering cannot lag behind more than 1 second
// behind decoding.
if (pts + 1 < min_pts)
pts = min_pts;
}
int last_needed = -1;
for (int n = 0; n < MAX_QUEUE; n++) {
struct sub *sub = &priv->subs[n];
if (!sub->valid)
continue;
if (pts == MP_NOPTS_VALUE ||
((sub->pts == MP_NOPTS_VALUE || sub->pts >= pts) ||
(sub->endpts == MP_NOPTS_VALUE || pts < sub->endpts)))
{
last_needed = n;
}
}
// We can accept a packet if it wouldn't overflow the fixed subtitle queue.
// We assume that get_bitmaps() never decreases the PTS.
return last_needed + 1 < MAX_QUEUE;
}
static void reset(struct sd *sd)
{
struct sd_lavc_priv *priv = sd->priv;
for (int n = 0; n < MAX_QUEUE; n++)
clear_sub(&priv->subs[n]);
// lavc might not do this right for all codecs; may need close+reopen
avcodec_flush_buffers(priv->avctx);
priv->current_pts = MP_NOPTS_VALUE;
}
static void uninit(struct sd *sd)
{
struct sd_lavc_priv *priv = sd->priv;
for (int n = 0; n < MAX_QUEUE; n++)
clear_sub(&priv->subs[n]);
avcodec_free_context(&priv->avctx);
talloc_free(priv);
}
static int compare_seekpoint(const void *pa, const void *pb)
{
const struct seekpoint *a = pa, *b = pb;
return a->pts == b->pts ? 0 : (a->pts < b->pts ? -1 : +1);
}
// taken from ass_step_sub(), libass (ISC)
static double step_sub(struct sd *sd, double now, int movement)
{
struct sd_lavc_priv *priv = sd->priv;
int best = -1;
double target = now;
int direction = (movement > 0 ? 1 : -1) * !!movement;
if (priv->num_seekpoints == 0)
return MP_NOPTS_VALUE;
qsort(priv->seekpoints, priv->num_seekpoints, sizeof(priv->seekpoints[0]),
compare_seekpoint);
do {
int closest = -1;
double closest_time = 0;
for (int i = 0; i < priv->num_seekpoints; i++) {
struct seekpoint *p = &priv->seekpoints[i];
double start = p->pts;
if (direction < 0) {
double end = p->endpts == MP_NOPTS_VALUE ? INFINITY : p->endpts;
if (end < target) {
if (closest < 0 || end > closest_time) {
closest = i;
closest_time = end;
}
}
} else if (direction > 0) {
if (start > target) {
if (closest < 0 || start < closest_time) {
closest = i;
closest_time = start;
}
}
} else {
if (start < target) {
if (closest < 0 || start >= closest_time) {
closest = i;
closest_time = start;
}
}
}
}
if (closest < 0)
break;
target = closest_time + direction;
best = closest;
movement -= direction;
} while (movement);
return best < 0 ? now : priv->seekpoints[best].pts;
}
static int control(struct sd *sd, enum sd_ctrl cmd, void *arg)
{
struct sd_lavc_priv *priv = sd->priv;
switch (cmd) {
case SD_CTRL_SUB_STEP: {
double *a = arg;
double res = step_sub(sd, a[0], a[1]);
if (res == MP_NOPTS_VALUE)
return false;
a[0] = res;
return true;
}
case SD_CTRL_SET_VIDEO_PARAMS:
priv->video_params = *(struct mp_image_params *)arg;
return CONTROL_OK;
default:
return CONTROL_UNKNOWN;
}
}
const struct sd_functions sd_lavc = {
.name = "lavc",
.init = init,
.decode = decode,
.get_bitmaps = get_bitmaps,
.accepts_packet = accepts_packet,
.control = control,
.reset = reset,
.uninit = uninit,
};