PeerStreamer

/*

 * DVB subtitle encoding for ffmpeg

 * Copyright (c) 2005 Fabrice Bellard.

 *

 * This library 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 of the License, or (at your option) any later version.

 *

 * This library 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 this library; if not, write to the Free Software

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

 */

#include "avcodec.h"

typedef struct DVBSubtitleContext {

    int hide_state;

    int object_version;

} DVBSubtitleContext;

#define PUTBITS2(val)\

{\

    bitbuf |= (val) << bitcnt;\

    bitcnt -= 2;\

    if (bitcnt < 0) {\

        bitcnt = 6;\

        *q++ = bitbuf;\

        bitbuf = 0;\

    }\

}

static void dvb_encode_rle2(uint8_t **pq,

                            const uint8_t *bitmap, int linesize,

                            int w, int h)

{

    uint8_t *q;

    unsigned int bitbuf;

    int bitcnt;

    int x, y, len, x1, v, color;

    q = *pq;

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

        *q++ = 0x10;

        bitbuf = 0;

        bitcnt = 6;

        x = 0;

        while (x < w) {

            x1 = x;

            color = bitmap[x1++];

            while (x1 < w && bitmap[x1] == color)

                x1++;

            len = x1 - x;

            if (color == 0 && len == 2) {

                PUTBITS2(0);

                PUTBITS2(0);

                PUTBITS2(1);

            } else if (len >= 3 && len <= 10) {

                v = len - 3;

                PUTBITS2(0);

                PUTBITS2((v >> 2) | 2);

                PUTBITS2(v & 3);

                PUTBITS2(color);

            } else if (len >= 12 && len <= 27) {

                v = len - 12;

                PUTBITS2(0);

                PUTBITS2(0);

                PUTBITS2(2);

                PUTBITS2(v >> 2);

                PUTBITS2(v & 3);

                PUTBITS2(color);

            } else if (len >= 29) {

                /* length = 29 ... 284 */

                if (len > 284)

                    len = 284;

                v = len - 29;

                PUTBITS2(0);

                PUTBITS2(0);

                PUTBITS2(3);

                PUTBITS2((v >> 6));

                PUTBITS2((v >> 4) & 3);

                PUTBITS2((v >> 2) & 3);

                PUTBITS2(v & 3);

                PUTBITS2(color);

            } else {

                PUTBITS2(color);

                if (color == 0) {

                    PUTBITS2(1);

                }

                len = 1;

            }

            x += len;

        }

        /* end of line */

        PUTBITS2(0);

        PUTBITS2(0);

        PUTBITS2(0);

        if (bitcnt != 6) {

            *q++ = bitbuf;

        }

        *q++ = 0xf0;

        bitmap += linesize;

    }

    *pq = q;

}

#define PUTBITS4(val)\

{\

    bitbuf |= (val) << bitcnt;\

    bitcnt -= 4;\

    if (bitcnt < 0) {\

        bitcnt = 4;\

        *q++ = bitbuf;\

        bitbuf = 0;\

    }\

}

/* some DVB decoders only implement 4 bits/pixel */

static void dvb_encode_rle4(uint8_t **pq,

                            const uint8_t *bitmap, int linesize,

                            int w, int h)

{

    uint8_t *q;

    unsigned int bitbuf;

    int bitcnt;

    int x, y, len, x1, v, color;

    q = *pq;

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

        *q++ = 0x11;

        bitbuf = 0;

        bitcnt = 4;

        x = 0;

        while (x < w) {

            x1 = x;

            color = bitmap[x1++];

            while (x1 < w && bitmap[x1] == color)

                x1++;

            len = x1 - x;

            if (color == 0 && len == 2) {

                PUTBITS4(0);

                PUTBITS4(0xd);

            } else if (color == 0 && (len >= 3 && len <= 9)) {

                PUTBITS4(0);

                PUTBITS4(len - 2);

            } else if (len >= 4 && len <= 7) {

                PUTBITS4(0);

                PUTBITS4(8 + len - 4);

                PUTBITS4(color);

            } else if (len >= 9 && len <= 24) {

                PUTBITS4(0);

                PUTBITS4(0xe);

                PUTBITS4(len - 9);

                PUTBITS4(color);

            } else if (len >= 25) {

                if (len > 280)

                    len = 280;

                v = len - 25;

                PUTBITS4(0);

                PUTBITS4(0xf);

                PUTBITS4(v >> 4);

                PUTBITS4(v & 0xf);

                PUTBITS4(color);

            } else {

                PUTBITS4(color);

                if (color == 0) {

                    PUTBITS4(0xc);

                }

                len = 1;

            }

            x += len;

        }

        /* end of line */

        PUTBITS4(0);

        PUTBITS4(0);

        if (bitcnt != 4) {

            *q++ = bitbuf;

        }

        *q++ = 0xf0;

        bitmap += linesize;

    }

    *pq = q;

}

#define SCALEBITS 10

#define ONE_HALF  (1 << (SCALEBITS - 1))

#define FIX(x)    ((int) ((x) * (1<<SCALEBITS) + 0.5))

#define RGB_TO_Y_CCIR(r, g, b) \

((FIX(0.29900*219.0/255.0) * (r) + FIX(0.58700*219.0/255.0) * (g) + \

  FIX(0.11400*219.0/255.0) * (b) + (ONE_HALF + (16 << SCALEBITS))) >> SCALEBITS)

#define RGB_TO_U_CCIR(r1, g1, b1, shift)\

(((- FIX(0.16874*224.0/255.0) * r1 - FIX(0.33126*224.0/255.0) * g1 +         \

     FIX(0.50000*224.0/255.0) * b1 + (ONE_HALF << shift) - 1) >> (SCALEBITS + shift)) + 128)

#define RGB_TO_V_CCIR(r1, g1, b1, shift)\

(((FIX(0.50000*224.0/255.0) * r1 - FIX(0.41869*224.0/255.0) * g1 -           \

   FIX(0.08131*224.0/255.0) * b1 + (ONE_HALF << shift) - 1) >> (SCALEBITS + shift)) + 128)

static inline void putbe16(uint8_t **pq, uint16_t v)

{

    uint8_t *q;

    q = *pq;

    *q++ = v >> 8;

    *q++ = v;

    *pq = q;

}

static int encode_dvb_subtitles(DVBSubtitleContext *s,

                                uint8_t *outbuf, AVSubtitle *h)

{

    uint8_t *q, *pseg_len;

    int page_id, region_id, clut_id, object_id, i, bpp_index, page_state;

    q = outbuf;

    page_id = 1;

    if (h->num_rects == 0 || h->rects == NULL)

        return -1;

    *q++ = 0x00; /* subtitle_stream_id */

    /* page composition segment */

    *q++ = 0x0f; /* sync_byte */

    *q++ = 0x10; /* segment_type */

    putbe16(&q, page_id);

    pseg_len = q;

    q += 2; /* segment length */

    *q++ = 30; /* page_timeout (seconds) */

    if (s->hide_state)

        page_state = 0; /* normal case */

    else

        page_state = 2; /* mode change */

    /* page_version = 0 + page_state */

    *q++ = s->object_version | (page_state << 2) | 3;

    for (region_id = 0; region_id < h->num_rects; region_id++) {

        *q++ = region_id;

        *q++ = 0xff; /* reserved */

        putbe16(&q, h->rects[region_id].x); /* left pos */

        putbe16(&q, h->rects[region_id].y); /* top pos */

    }

    putbe16(&pseg_len, q - pseg_len - 2);

    if (!s->hide_state) {

        for (clut_id = 0; clut_id < h->num_rects; clut_id++) {

            /* CLUT segment */

            if (h->rects[clut_id].nb_colors <= 4) {

                /* 2 bpp, some decoders do not support it correctly */

                bpp_index = 0;

            } else if (h->rects[clut_id].nb_colors <= 16) {

                /* 4 bpp, standard encoding */

                bpp_index = 1;

            } else {

                return -1;

            }

            *q++ = 0x0f; /* sync byte */

            *q++ = 0x12; /* CLUT definition segment */

            putbe16(&q, page_id);

            pseg_len = q;

            q += 2; /* segment length */

            *q++ = clut_id;

            *q++ = (0 << 4) | 0xf; /* version = 0 */

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

                *q++ = i; /* clut_entry_id */

                *q++ = (1 << (7 - bpp_index)) | (0xf << 1) | 1; /* 2 bits/pixel full range */

                {

                    int a, r, g, b;

                    a = (h->rects[clut_id].rgba_palette[i] >> 24) & 0xff;

                    r = (h->rects[clut_id].rgba_palette[i] >> 16) & 0xff;

                    g = (h->rects[clut_id].rgba_palette[i] >> 8) & 0xff;

                    b = (h->rects[clut_id].rgba_palette[i] >> 0) & 0xff;

                    *q++ = RGB_TO_Y_CCIR(r, g, b);

                    *q++ = RGB_TO_V_CCIR(r, g, b, 0);

                    *q++ = RGB_TO_U_CCIR(r, g, b, 0);

                    *q++ = 255 - a;

                }

            }

            putbe16(&pseg_len, q - pseg_len - 2);

        }

    }

    for (region_id = 0; region_id < h->num_rects; region_id++) {

        /* region composition segment */

        if (h->rects[region_id].nb_colors <= 4) {

            /* 2 bpp, some decoders do not support it correctly */

            bpp_index = 0;

        } else if (h->rects[region_id].nb_colors <= 16) {

            /* 4 bpp, standard encoding */

            bpp_index = 1;

        } else {

            return -1;

        }

        *q++ = 0x0f; /* sync_byte */

        *q++ = 0x11; /* segment_type */

        putbe16(&q, page_id);

        pseg_len = q;

        q += 2; /* segment length */

        *q++ = region_id;

        *q++ = (s->object_version << 4) | (0 << 3) | 0x07; /* version , no fill */

        putbe16(&q, h->rects[region_id].w); /* region width */

        putbe16(&q, h->rects[region_id].h); /* region height */

        *q++ = ((1 + bpp_index) << 5) | ((1 + bpp_index) << 2) | 0x03;

        *q++ = region_id; /* clut_id == region_id */

        *q++ = 0; /* 8 bit fill colors */

        *q++ = 0x03; /* 4 bit and 2 bit fill colors */

        if (!s->hide_state) {

            putbe16(&q, region_id); /* object_id == region_id */

            *q++ = (0 << 6) | (0 << 4);

            *q++ = 0;

            *q++ = 0xf0;

            *q++ = 0;

        }

        putbe16(&pseg_len, q - pseg_len - 2);

    }

    if (!s->hide_state) {

        for (object_id = 0; object_id < h->num_rects; object_id++) {

            /* Object Data segment */

            if (h->rects[object_id].nb_colors <= 4) {

                /* 2 bpp, some decoders do not support it correctly */

                bpp_index = 0;

            } else if (h->rects[object_id].nb_colors <= 16) {

                /* 4 bpp, standard encoding */

                bpp_index = 1;

            } else {

                return -1;

            }

            *q++ = 0x0f; /* sync byte */

            *q++ = 0x13;

            putbe16(&q, page_id);

            pseg_len = q;

            q += 2; /* segment length */

            putbe16(&q, object_id);

            *q++ = (s->object_version << 4) | (0 << 2) | (0 << 1) | 1; /* version = 0,

                                                                       onject_coding_method,

                                                                       non_modifying_color_flag */

            {

                uint8_t *ptop_field_len, *pbottom_field_len, *top_ptr, *bottom_ptr;

                void (*dvb_encode_rle)(uint8_t **pq,

                                        const uint8_t *bitmap, int linesize,

                                        int w, int h);

                ptop_field_len = q;

                q += 2;

                pbottom_field_len = q;

                q += 2;

                if (bpp_index == 0)

                    dvb_encode_rle = dvb_encode_rle2;

                else

                    dvb_encode_rle = dvb_encode_rle4;

                top_ptr = q;

                dvb_encode_rle(&q, h->rects[object_id].bitmap, h->rects[object_id].w * 2,

                                    h->rects[object_id].w, h->rects[object_id].h >> 1);

                bottom_ptr = q;

                dvb_encode_rle(&q, h->rects[object_id].bitmap + h->rects[object_id].w,

                                    h->rects[object_id].w * 2, h->rects[object_id].w,

                                    h->rects[object_id].h >> 1);

                putbe16(&ptop_field_len, bottom_ptr - top_ptr);

                putbe16(&pbottom_field_len, q - bottom_ptr);

            }

            putbe16(&pseg_len, q - pseg_len - 2);

        }

    }

    /* end of display set segment */

    *q++ = 0x0f; /* sync_byte */

    *q++ = 0x80; /* segment_type */

    putbe16(&q, page_id);

    pseg_len = q;

    q += 2; /* segment length */

    putbe16(&pseg_len, q - pseg_len - 2);

    *q++ = 0xff; /* end of PES data */

    s->object_version = (s->object_version + 1) & 0xf;

    s->hide_state = !s->hide_state;

    return q - outbuf;

}

static int dvbsub_init_decoder(AVCodecContext *avctx)

{

    return 0;

}

static int dvbsub_close_decoder(AVCodecContext *avctx)

{

    return 0;

}

static int dvbsub_encode(AVCodecContext *avctx,

                       unsigned char *buf, int buf_size, void *data)

{

    DVBSubtitleContext *s = avctx->priv_data;

    AVSubtitle *sub = data;

    int ret;

    ret = encode_dvb_subtitles(s, buf, sub);

    return ret;

}

AVCodec dvbsub_encoder = {

    "dvbsub",

    CODEC_TYPE_SUBTITLE,

    CODEC_ID_DVB_SUBTITLE,

    sizeof(DVBSubtitleContext),

    dvbsub_init_decoder,

    dvbsub_encode,

    dvbsub_close_decoder,

};