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/*

 * DVD subtitle decoding

 * Copyright (c) 2005 Fabrice Bellard

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg 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.

 *

 * FFmpeg 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 FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include "avcodec.h"

#include "get_bits.h"

#include "dsputil.h"

#include "libavutil/attributes.h"

#include "libavutil/colorspace.h"

#include "libavutil/opt.h"

#include "libavutil/imgutils.h"

#include "libavutil/avstring.h"

typedef struct DVDSubContext

{

  AVClass *class;

  uint32_t palette[16];

  char    *palette_str;

  int      has_palette;

  uint8_t  colormap[4];

  uint8_t  alpha[256];

  uint8_t *buf;

  int      buf_size;

#ifdef DEBUG

  int sub_id;

#endif

} DVDSubContext;

static void yuv_a_to_rgba(const uint8_t *ycbcr, const uint8_t *alpha, uint32_t *rgba, int num_values)

{

    const uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;

    uint8_t r, g, b;

    int i, y, cb, cr;

    int r_add, g_add, b_add;

    for (i = num_values; i > 0; i--) {

        y = *ycbcr++;

        cr = *ycbcr++;

        cb = *ycbcr++;

        YUV_TO_RGB1_CCIR(cb, cr);

        YUV_TO_RGB2_CCIR(r, g, b, y);

        *rgba++ = (*alpha++ << 24) | (r << 16) | (g << 8) | b;

    }

}

static int decode_run_2bit(GetBitContext *gb, int *color)

{

    unsigned int v, t;

    v = 0;

    for (t = 1; v < t && t <= 0x40; t <<= 2)

        v = (v << 4) | get_bits(gb, 4);

    *color = v & 3;

    if (v < 4) { /* Code for fill rest of line */

        return INT_MAX;

    }

    return v >> 2;

}

static int decode_run_8bit(GetBitContext *gb, int *color)

{

    int len;

    int has_run = get_bits1(gb);

    if (get_bits1(gb))

        *color = get_bits(gb, 8);

    else

        *color = get_bits(gb, 2);

    if (has_run) {

        if (get_bits1(gb)) {

            len = get_bits(gb, 7);

            if (len == 0)

                len = INT_MAX;

            else

                len += 9;

        } else

            len = get_bits(gb, 3) + 2;

    } else

        len = 1;

    return len;

}

static int decode_rle(uint8_t *bitmap, int linesize, int w, int h,

                      const uint8_t *buf, int start, int buf_size, int is_8bit)

{

    GetBitContext gb;

    int bit_len;

    int x, y, len, color;

    uint8_t *d;

    bit_len = (buf_size - start) * 8;

    init_get_bits(&gb, buf + start, bit_len);

    x = 0;

    y = 0;

    d = bitmap;

    for(;;) {

        if (get_bits_count(&gb) > bit_len)

            return -1;

        if (is_8bit)

            len = decode_run_8bit(&gb, &color);

        else

            len = decode_run_2bit(&gb, &color);

        len = FFMIN(len, w - x);

        memset(d + x, color, len);

        x += len;

        if (x >= w) {

            y++;

            if (y >= h)

                break;

            d += linesize;

            x = 0;

            /* byte align */

            align_get_bits(&gb);

        }

    }

    return 0;

}

static void guess_palette(DVDSubContext* ctx,

                          uint32_t *rgba_palette,

                          uint32_t subtitle_color)

{

    static const uint8_t level_map[4][4] = {

        // this configuration (full range, lowest to highest) in tests

        // seemed most common, so assume this

        {0xff},

        {0x00, 0xff},

        {0x00, 0x80, 0xff},

        {0x00, 0x55, 0xaa, 0xff},

    };

    uint8_t color_used[16] = { 0 };

    int nb_opaque_colors, i, level, j, r, g, b;

    uint8_t *colormap = ctx->colormap, *alpha = ctx->alpha;

    if(ctx->has_palette) {

        for(i = 0; i < 4; i++)

            rgba_palette[i] = (ctx->palette[colormap[i]] & 0x00ffffff)

                              | ((alpha[i] * 17U) << 24);

        return;

    }

    for(i = 0; i < 4; i++)

        rgba_palette[i] = 0;

    nb_opaque_colors = 0;

    for(i = 0; i < 4; i++) {

        if (alpha[i] != 0 && !color_used[colormap[i]]) {

            color_used[colormap[i]] = 1;

            nb_opaque_colors++;

        }

    }

    if (nb_opaque_colors == 0)

        return;

    j = 0;

    memset(color_used, 0, 16);

    for(i = 0; i < 4; i++) {

        if (alpha[i] != 0) {

            if (!color_used[colormap[i]])  {

                level = level_map[nb_opaque_colors][j];

                r = (((subtitle_color >> 16) & 0xff) * level) >> 8;

                g = (((subtitle_color >> 8) & 0xff) * level) >> 8;

                b = (((subtitle_color >> 0) & 0xff) * level) >> 8;

                rgba_palette[i] = b | (g << 8) | (r << 16) | ((alpha[i] * 17) << 24);

                color_used[colormap[i]] = (i + 1);

                j++;

            } else {

                rgba_palette[i] = (rgba_palette[color_used[colormap[i]] - 1] & 0x00ffffff) |

                                    ((alpha[i] * 17) << 24);

            }

        }

    }

}

static void reset_rects(AVSubtitle *sub_header)

{

    int i;

    if (sub_header->rects != NULL) {

        for (i = 0; i < sub_header->num_rects; i++) {

            av_freep(&sub_header->rects[i]->pict.data[0]);

            av_freep(&sub_header->rects[i]->pict.data[1]);

            av_freep(&sub_header->rects[i]);

        }

        av_freep(&sub_header->rects);

        sub_header->num_rects = 0;

    }

}

#define READ_OFFSET(a) (big_offsets ? AV_RB32(a) : AV_RB16(a))

static int decode_dvd_subtitles(DVDSubContext *ctx, AVSubtitle *sub_header,

                                const uint8_t *buf, int buf_size)

{

    int cmd_pos, pos, cmd, x1, y1, x2, y2, offset1, offset2, next_cmd_pos;

    int big_offsets, offset_size, is_8bit = 0;

    const uint8_t *yuv_palette = 0;

    uint8_t *colormap = ctx->colormap, *alpha = ctx->alpha;

    int date;

    int i;

    int is_menu = 0;

    if (buf_size < 10)

        return -1;

    if (AV_RB16(buf) == 0) {   /* HD subpicture with 4-byte offsets */

        big_offsets = 1;

        offset_size = 4;

        cmd_pos = 6;

    } else {

        big_offsets = 0;

        offset_size = 2;

        cmd_pos = 2;

    }

    cmd_pos = READ_OFFSET(buf + cmd_pos);

    if (cmd_pos < 0 || cmd_pos > buf_size - 2 - offset_size)

        return AVERROR(EAGAIN);

    while (cmd_pos > 0 && cmd_pos < buf_size - 2 - offset_size) {

        date = AV_RB16(buf + cmd_pos);

        next_cmd_pos = READ_OFFSET(buf + cmd_pos + 2);

        av_dlog(NULL, "cmd_pos=0x%04x next=0x%04x date=%d\n",

                cmd_pos, next_cmd_pos, date);

        pos = cmd_pos + 2 + offset_size;

        offset1 = -1;

        offset2 = -1;

        x1 = y1 = x2 = y2 = 0;

        while (pos < buf_size) {

            cmd = buf[pos++];

            av_dlog(NULL, "cmd=%02x\n", cmd);

            switch(cmd) {

            case 0x00:

                /* menu subpicture */

                is_menu = 1;

                break;

            case 0x01:

                /* set start date */

                sub_header->start_display_time = (date << 10) / 90;

                break;

            case 0x02:

                /* set end date */

                sub_header->end_display_time = (date << 10) / 90;

                break;

            case 0x03:

                /* set colormap */

                if ((buf_size - pos) < 2)

                    goto fail;

                colormap[3] = buf[pos] >> 4;

                colormap[2] = buf[pos] & 0x0f;

                colormap[1] = buf[pos + 1] >> 4;

                colormap[0] = buf[pos + 1] & 0x0f;

                pos += 2;

                break;

            case 0x04:

                /* set alpha */

                if ((buf_size - pos) < 2)

                    goto fail;

                alpha[3] = buf[pos] >> 4;

                alpha[2] = buf[pos] & 0x0f;

                alpha[1] = buf[pos + 1] >> 4;

                alpha[0] = buf[pos + 1] & 0x0f;

                pos += 2;

            av_dlog(NULL, "alpha=%x%x%x%x\n", alpha[0],alpha[1],alpha[2],alpha[3]);

                break;

            case 0x05:

            case 0x85:

                if ((buf_size - pos) < 6)

                    goto fail;

                x1 = (buf[pos] << 4) | (buf[pos + 1] >> 4);

                x2 = ((buf[pos + 1] & 0x0f) << 8) | buf[pos + 2];

                y1 = (buf[pos + 3] << 4) | (buf[pos + 4] >> 4);

                y2 = ((buf[pos + 4] & 0x0f) << 8) | buf[pos + 5];

                if (cmd & 0x80)

                    is_8bit = 1;

                av_dlog(NULL, "x1=%d x2=%d y1=%d y2=%d\n", x1, x2, y1, y2);

                pos += 6;

                break;

            case 0x06:

                if ((buf_size - pos) < 4)

                    goto fail;

                offset1 = AV_RB16(buf + pos);

                offset2 = AV_RB16(buf + pos + 2);

                av_dlog(NULL, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);

                pos += 4;

                break;

            case 0x86:

                if ((buf_size - pos) < 8)

                    goto fail;

                offset1 = AV_RB32(buf + pos);

                offset2 = AV_RB32(buf + pos + 4);

                av_dlog(NULL, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);

                pos += 8;

                break;

            case 0x83:

                /* HD set palette */

                if ((buf_size - pos) < 768)

                    goto fail;

                yuv_palette = buf + pos;

                pos += 768;

                break;

            case 0x84:

                /* HD set contrast (alpha) */

                if ((buf_size - pos) < 256)

                    goto fail;

                for (i = 0; i < 256; i++)

                    alpha[i] = 0xFF - buf[pos+i];

                pos += 256;

                break;

            case 0xff:

                goto the_end;

            default:

                av_dlog(NULL, "unrecognised subpicture command 0x%x\n", cmd);

                goto the_end;

            }

        }

    the_end:

        if (offset1 >= 0) {

            int w, h;

            uint8_t *bitmap;

            /* decode the bitmap */

            w = x2 - x1 + 1;

            if (w < 0)

                w = 0;

            h = y2 - y1;

            if (h < 0)

                h = 0;

            if (w > 0 && h > 0) {

                reset_rects(sub_header);

                bitmap = av_malloc(w * h);

                sub_header->rects = av_mallocz(sizeof(*sub_header->rects));

                sub_header->rects[0] = av_mallocz(sizeof(AVSubtitleRect));

                sub_header->num_rects = 1;

                sub_header->rects[0]->pict.data[0] = bitmap;

                decode_rle(bitmap, w * 2, w, (h + 1) / 2,

                           buf, offset1, buf_size, is_8bit);

                decode_rle(bitmap + w, w * 2, w, h / 2,

                           buf, offset2, buf_size, is_8bit);

                sub_header->rects[0]->pict.data[1] = av_mallocz(AVPALETTE_SIZE);

                if (is_8bit) {

                    if (yuv_palette == 0)

                        goto fail;

                    sub_header->rects[0]->nb_colors = 256;

                    yuv_a_to_rgba(yuv_palette, alpha, (uint32_t*)sub_header->rects[0]->pict.data[1], 256);

                } else {

                    sub_header->rects[0]->nb_colors = 4;

                    guess_palette(ctx, (uint32_t*)sub_header->rects[0]->pict.data[1],

                                  0xffff00);

                }

                sub_header->rects[0]->x = x1;

                sub_header->rects[0]->y = y1;

                sub_header->rects[0]->w = w;

                sub_header->rects[0]->h = h;

                sub_header->rects[0]->type = SUBTITLE_BITMAP;

                sub_header->rects[0]->pict.linesize[0] = w;

                sub_header->rects[0]->flags = is_menu ? AV_SUBTITLE_FLAG_FORCED : 0;

            }

        }

        if (next_cmd_pos < cmd_pos) {

            av_log(NULL, AV_LOG_ERROR, "Invalid command offset\n");

            break;

        }

        if (next_cmd_pos == cmd_pos)

            break;

        cmd_pos = next_cmd_pos;

    }

    if (sub_header->num_rects > 0)

        return is_menu;

 fail:

    reset_rects(sub_header);

    return -1;

}

static int is_transp(const uint8_t *buf, int pitch, int n,

                     const uint8_t *transp_color)

{

    int i;

    for(i = 0; i < n; i++) {

        if (!transp_color[*buf])

            return 0;

        buf += pitch;

    }

    return 1;

}

/* return 0 if empty rectangle, 1 if non empty */

static int find_smallest_bounding_rectangle(AVSubtitle *s)

{

    uint8_t transp_color[256] = { 0 };

    int y1, y2, x1, x2, y, w, h, i;

    uint8_t *bitmap;

    if (s->num_rects == 0 || s->rects == NULL || s->rects[0]->w <= 0 || s->rects[0]->h <= 0)

        return 0;

    for(i = 0; i < s->rects[0]->nb_colors; i++) {

        if ((((uint32_t*)s->rects[0]->pict.data[1])[i] >> 24) == 0)

            transp_color[i] = 1;

    }

    y1 = 0;

    while (y1 < s->rects[0]->h && is_transp(s->rects[0]->pict.data[0] + y1 * s->rects[0]->pict.linesize[0],

                                  1, s->rects[0]->w, transp_color))

        y1++;

    if (y1 == s->rects[0]->h) {

        av_freep(&s->rects[0]->pict.data[0]);

        s->rects[0]->w = s->rects[0]->h = 0;

        return 0;

    }

    y2 = s->rects[0]->h - 1;

    while (y2 > 0 && is_transp(s->rects[0]->pict.data[0] + y2 * s->rects[0]->pict.linesize[0], 1,

                               s->rects[0]->w, transp_color))

        y2--;

    x1 = 0;

    while (x1 < (s->rects[0]->w - 1) && is_transp(s->rects[0]->pict.data[0] + x1, s->rects[0]->pict.linesize[0],

                                        s->rects[0]->h, transp_color))

        x1++;

    x2 = s->rects[0]->w - 1;

    while (x2 > 0 && is_transp(s->rects[0]->pict.data[0] + x2, s->rects[0]->pict.linesize[0], s->rects[0]->h,

                                  transp_color))

        x2--;

    w = x2 - x1 + 1;

    h = y2 - y1 + 1;

    bitmap = av_malloc(w * h);

    if (!bitmap)

        return 1;

    for(y = 0; y < h; y++) {

        memcpy(bitmap + w * y, s->rects[0]->pict.data[0] + x1 + (y1 + y) * s->rects[0]->pict.linesize[0], w);

    }

    av_freep(&s->rects[0]->pict.data[0]);

    s->rects[0]->pict.data[0] = bitmap;

    s->rects[0]->pict.linesize[0] = w;

    s->rects[0]->w = w;

    s->rects[0]->h = h;

    s->rects[0]->x += x1;

    s->rects[0]->y += y1;

    return 1;

}

#ifdef DEBUG

#undef fprintf

#undef perror

#undef exit

static void ppm_save(const char *filename, uint8_t *bitmap, int w, int h,

                     uint32_t *rgba_palette)

{

    int x, y, v;

    FILE *f;

    f = fopen(filename, "w");

    if (!f) {

        perror(filename);

        exit(1);

    }

    fprintf(f, "P6\n"

            "%d %d\n"

            "%d\n",

            w, h, 255);

    for(y = 0; y < h; y++) {

        for(x = 0; x < w; x++) {

            v = rgba_palette[bitmap[y * w + x]];

            putc((v >> 16) & 0xff, f);

            putc((v >> 8) & 0xff, f);

            putc((v >> 0) & 0xff, f);

        }

    }

    fclose(f);

}

#endif

static int append_to_cached_buf(AVCodecContext *avctx,

                                const uint8_t *buf, int buf_size)

{

    DVDSubContext *ctx = avctx->priv_data;

    if (ctx->buf_size > 0xffff - buf_size) {

        av_log(avctx, AV_LOG_WARNING, "Attempt to reconstruct "

               "too large SPU packets aborted.\n");

        av_freep(&ctx->buf);

        return AVERROR_INVALIDDATA;

    }

    ctx->buf = av_realloc(ctx->buf, ctx->buf_size + buf_size);

    if (!ctx->buf)

        return AVERROR(ENOMEM);

    memcpy(ctx->buf + ctx->buf_size, buf, buf_size);

    ctx->buf_size += buf_size;

    return 0;

}

static int dvdsub_decode(AVCodecContext *avctx,

                         void *data, int *data_size,

                         AVPacket *avpkt)

{

    DVDSubContext *ctx = avctx->priv_data;

    const uint8_t *buf = avpkt->data;

    int buf_size = avpkt->size;

    AVSubtitle *sub = data;

    int is_menu;

    if (ctx->buf) {

        int ret = append_to_cached_buf(avctx, buf, buf_size);

        if (ret < 0) {

            *data_size = 0;

            return ret;

        }

        buf = ctx->buf;

        buf_size = ctx->buf_size;

    }

    is_menu = decode_dvd_subtitles(ctx, sub, buf, buf_size);

    if (is_menu == AVERROR(EAGAIN)) {

        *data_size = 0;

        return append_to_cached_buf(avctx, buf, buf_size);

    }

    if (is_menu < 0) {

    no_subtitle:

        *data_size = 0;

        return buf_size;

    }

    if (!is_menu && find_smallest_bounding_rectangle(sub) == 0)

        goto no_subtitle;

#if defined(DEBUG)

    {

    char ppm_name[32];

    snprintf(ppm_name, sizeof(ppm_name), "/tmp/%05d.ppm", ctx->sub_id++);

    av_dlog(NULL, "start=%d ms end =%d ms\n",

            sub->start_display_time,

            sub->end_display_time);

    ppm_save(ppm_name, sub->rects[0]->pict.data[0],

             sub->rects[0]->w, sub->rects[0]->h, sub->rects[0]->pict.data[1]);

    }

#endif

    av_freep(&ctx->buf);

    ctx->buf_size = 0;

    *data_size = 1;

    return buf_size;

}

static void parse_palette(DVDSubContext *ctx, char *p)

{

    int i;

    ctx->has_palette = 1;

    for(i=0;i<16;i++) {

        ctx->palette[i] = strtoul(p, &p, 16);

        while(*p == ',' || av_isspace(*p))

            p++;

    }

}

static int dvdsub_parse_extradata(AVCodecContext *avctx)

{

    DVDSubContext *ctx = (DVDSubContext*) avctx->priv_data;

    char *dataorig, *data;

    if (!avctx->extradata || !avctx->extradata_size)

        return 1;

    dataorig = data = av_malloc(avctx->extradata_size+1);

    if (!data)

        return AVERROR(ENOMEM);

    memcpy(data, avctx->extradata, avctx->extradata_size);

    data[avctx->extradata_size] = '\0';

    for(;;) {

        int pos = strcspn(data, "\n\r");

        if (pos==0 && *data==0)

            break;

        if (strncmp("palette:", data, 8) == 0) {

            parse_palette(ctx, data + 8);

        } else if (strncmp("size:", data, 5) == 0) {

            int w, h;

            if (sscanf(data + 5, "%dx%d", &w, &h) == 2 &&

                av_image_check_size(w, h, 0, avctx) >= 0)

                avcodec_set_dimensions(avctx, w, h);

        }

        data += pos;

        data += strspn(data, "\n\r");

    }

    av_free(dataorig);

    return 1;

}

static av_cold int dvdsub_init(AVCodecContext *avctx)

{

    DVDSubContext *ctx = avctx->priv_data;

    int ret;

    if ((ret = dvdsub_parse_extradata(avctx)) < 0)

        return ret;

    if (ctx->palette_str)

        parse_palette(ctx, ctx->palette_str);

    if (ctx->has_palette) {

        int i;

        av_log(avctx, AV_LOG_DEBUG, "palette:");

        for(i=0;i<16;i++)

            av_log(avctx, AV_LOG_DEBUG, " 0x%06x", ctx->palette[i]);

        av_log(avctx, AV_LOG_DEBUG, "\n");

    }

    return 1;

}

static av_cold int dvdsub_close(AVCodecContext *avctx)

{

    DVDSubContext *ctx = avctx->priv_data;

    av_freep(&ctx->buf);

    ctx->buf_size = 0;

    return 0;

}

#define OFFSET(field) offsetof(DVDSubContext, field)

#define VD AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_DECODING_PARAM

static const AVOption options[] = {

    { "palette", "set the global palette", OFFSET(palette_str), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, VD },

    { NULL }

};

static const AVClass dvdsub_class = {

    .class_name = "dvdsubdec",

    .item_name  = av_default_item_name,

    .option     = options,

    .version    = LIBAVUTIL_VERSION_INT,

};

AVCodec ff_dvdsub_decoder = {

    .name           = "dvdsub",

    .long_name      = NULL_IF_CONFIG_SMALL("DVD subtitles"),

    .type           = AVMEDIA_TYPE_SUBTITLE,

    .id             = AV_CODEC_ID_DVD_SUBTITLE,

    .priv_data_size = sizeof(DVDSubContext),

    .init           = dvdsub_init,

    .decode         = dvdsub_decode,

    .close          = dvdsub_close,

    .priv_class     = &dvdsub_class,

};