PeerStreamer

/*

 * DVB subtitle decoding for ffmpeg

 * Copyright (c) 2005 Ian Caulfield

 *

 * 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 "dsputil.h"

#include "get_bits.h"

#include "colorspace.h"

//#define DEBUG

//#define DEBUG_PACKET_CONTENTS

//#define DEBUG_SAVE_IMAGES

#define DVBSUB_PAGE_SEGMENT     0x10

#define DVBSUB_REGION_SEGMENT   0x11

#define DVBSUB_CLUT_SEGMENT     0x12

#define DVBSUB_OBJECT_SEGMENT   0x13

#define DVBSUB_DISPLAY_SEGMENT  0x80

#define cm (ff_cropTbl + MAX_NEG_CROP)

#ifdef DEBUG_SAVE_IMAGES

#undef fprintf

#if 0

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

                     uint32_t *rgba_palette)

{

    int x, y, v;

    FILE *f;

    char fname[40], fname2[40];

    char command[1024];

    snprintf(fname, 40, "%s.ppm", filename);

    f = fopen(fname, "w");

    if (!f) {

        perror(fname);

        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);

    snprintf(fname2, 40, "%s-a.pgm", filename);

    f = fopen(fname2, "w");

    if (!f) {

        perror(fname2);

        exit(1);

    }

    fprintf(f, "P5\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 >> 24) & 0xff, f);

        }

    }

    fclose(f);

    snprintf(command, 1024, "pnmtopng -alpha %s %s > %s.png 2> /dev/null", fname2, fname, filename);

    system(command);

    snprintf(command, 1024, "rm %s %s", fname, fname2);

    system(command);

}

#endif

static void png_save2(const char *filename, uint32_t *bitmap, int w, int h)

{

    int x, y, v;

    FILE *f;

    char fname[40], fname2[40];

    char command[1024];

    snprintf(fname, sizeof(fname), "%s.ppm", filename);

    f = fopen(fname, "w");

    if (!f) {

        perror(fname);

        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 = bitmap[y * w + x];

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

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

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

        }

    }

    fclose(f);

    snprintf(fname2, sizeof(fname2), "%s-a.pgm", filename);

    f = fopen(fname2, "w");

    if (!f) {

        perror(fname2);

        exit(1);

    }

    fprintf(f, "P5\n"

            "%d %d\n"

            "%d\n",

            w, h, 255);

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

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

            v = bitmap[y * w + x];

            putc((v >> 24) & 0xff, f);

        }

    }

    fclose(f);

    snprintf(command, sizeof(command), "pnmtopng -alpha %s %s > %s.png 2> /dev/null", fname2, fname, filename);

    system(command);

    snprintf(command, sizeof(command), "rm %s %s", fname, fname2);

    system(command);

}

#endif

#define RGBA(r,g,b,a) (((a) << 24) | ((r) << 16) | ((g) << 8) | (b))

typedef struct DVBSubCLUT {

    int id;

    uint32_t clut4[4];

    uint32_t clut16[16];

    uint32_t clut256[256];

    struct DVBSubCLUT *next;

} DVBSubCLUT;

static DVBSubCLUT default_clut;

typedef struct DVBSubObjectDisplay {

    int object_id;

    int region_id;

    int x_pos;

    int y_pos;

    int fgcolor;

    int bgcolor;

    struct DVBSubObjectDisplay *region_list_next;

    struct DVBSubObjectDisplay *object_list_next;

} DVBSubObjectDisplay;

typedef struct DVBSubObject {

    int id;

    int type;

    DVBSubObjectDisplay *display_list;

    struct DVBSubObject *next;

} DVBSubObject;

typedef struct DVBSubRegionDisplay {

    int region_id;

    int x_pos;

    int y_pos;

    struct DVBSubRegionDisplay *next;

} DVBSubRegionDisplay;

typedef struct DVBSubRegion {

    int id;

    int width;

    int height;

    int depth;

    int clut;

    int bgcolor;

    uint8_t *pbuf;

    int buf_size;

    DVBSubObjectDisplay *display_list;

    struct DVBSubRegion *next;

} DVBSubRegion;

typedef struct DVBSubContext {

    int composition_id;

    int ancillary_id;

    int time_out;

    DVBSubRegion *region_list;

    DVBSubCLUT   *clut_list;

    DVBSubObject *object_list;

    int display_list_size;

    DVBSubRegionDisplay *display_list;

} DVBSubContext;

static DVBSubObject* get_object(DVBSubContext *ctx, int object_id)

{

    DVBSubObject *ptr = ctx->object_list;

    while (ptr && ptr->id != object_id) {

        ptr = ptr->next;

    }

    return ptr;

}

static DVBSubCLUT* get_clut(DVBSubContext *ctx, int clut_id)

{

    DVBSubCLUT *ptr = ctx->clut_list;

    while (ptr && ptr->id != clut_id) {

        ptr = ptr->next;

    }

    return ptr;

}

static DVBSubRegion* get_region(DVBSubContext *ctx, int region_id)

{

    DVBSubRegion *ptr = ctx->region_list;

    while (ptr && ptr->id != region_id) {

        ptr = ptr->next;

    }

    return ptr;

}

static void delete_region_display_list(DVBSubContext *ctx, DVBSubRegion *region)

{

    DVBSubObject *object, *obj2, **obj2_ptr;

    DVBSubObjectDisplay *display, *obj_disp, **obj_disp_ptr;

    while (region->display_list) {

        display = region->display_list;

        object = get_object(ctx, display->object_id);

        if (object) {

            obj_disp_ptr = &object->display_list;

            obj_disp = *obj_disp_ptr;

            while (obj_disp && obj_disp != display) {

                obj_disp_ptr = &obj_disp->object_list_next;

                obj_disp = *obj_disp_ptr;

            }

            if (obj_disp) {

                *obj_disp_ptr = obj_disp->object_list_next;

                if (!object->display_list) {

                    obj2_ptr = &ctx->object_list;

                    obj2 = *obj2_ptr;

                    while (obj2 != object) {

                        assert(obj2);

                        obj2_ptr = &obj2->next;

                        obj2 = *obj2_ptr;

                    }

                    *obj2_ptr = obj2->next;

                    av_free(obj2);

                }

            }

        }

        region->display_list = display->region_list_next;

        av_free(display);

    }

}

static void delete_state(DVBSubContext *ctx)

{

    DVBSubRegion *region;

    DVBSubCLUT *clut;

    while (ctx->region_list) {

        region = ctx->region_list;

        ctx->region_list = region->next;

        delete_region_display_list(ctx, region);

        if (region->pbuf)

            av_free(region->pbuf);

        av_free(region);

    }

    while (ctx->clut_list) {

        clut = ctx->clut_list;

        ctx->clut_list = clut->next;

        av_free(clut);

    }

    /* Should already be null */

    if (ctx->object_list)

        av_log(0, AV_LOG_ERROR, "Memory deallocation error!\n");

}

static av_cold int dvbsub_init_decoder(AVCodecContext *avctx)

{

    int i, r, g, b, a = 0;

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

    memset(avctx->priv_data, 0, sizeof(DVBSubContext));

    ctx->composition_id = avctx->sub_id & 0xffff;

    ctx->ancillary_id = avctx->sub_id >> 16;

    default_clut.id = -1;

    default_clut.next = NULL;

    default_clut.clut4[0] = RGBA(  0,   0,   0,   0);

    default_clut.clut4[1] = RGBA(255, 255, 255, 255);

    default_clut.clut4[2] = RGBA(  0,   0,   0, 255);

    default_clut.clut4[3] = RGBA(127, 127, 127, 255);

    default_clut.clut16[0] = RGBA(  0,   0,   0,   0);

    for (i = 1; i < 16; i++) {

        if (i < 8) {

            r = (i & 1) ? 255 : 0;

            g = (i & 2) ? 255 : 0;

            b = (i & 4) ? 255 : 0;

        } else {

            r = (i & 1) ? 127 : 0;

            g = (i & 2) ? 127 : 0;

            b = (i & 4) ? 127 : 0;

        }

        default_clut.clut16[i] = RGBA(r, g, b, 255);

    }

    default_clut.clut256[0] = RGBA(  0,   0,   0,   0);

    for (i = 1; i < 256; i++) {

        if (i < 8) {

            r = (i & 1) ? 255 : 0;

            g = (i & 2) ? 255 : 0;

            b = (i & 4) ? 255 : 0;

            a = 63;

        } else {

            switch (i & 0x88) {

            case 0x00:

                r = ((i & 1) ? 85 : 0) + ((i & 0x10) ? 170 : 0);

                g = ((i & 2) ? 85 : 0) + ((i & 0x20) ? 170 : 0);

                b = ((i & 4) ? 85 : 0) + ((i & 0x40) ? 170 : 0);

                a = 255;

                break;

            case 0x08:

                r = ((i & 1) ? 85 : 0) + ((i & 0x10) ? 170 : 0);

                g = ((i & 2) ? 85 : 0) + ((i & 0x20) ? 170 : 0);

                b = ((i & 4) ? 85 : 0) + ((i & 0x40) ? 170 : 0);

                a = 127;

                break;

            case 0x80:

                r = 127 + ((i & 1) ? 43 : 0) + ((i & 0x10) ? 85 : 0);

                g = 127 + ((i & 2) ? 43 : 0) + ((i & 0x20) ? 85 : 0);

                b = 127 + ((i & 4) ? 43 : 0) + ((i & 0x40) ? 85 : 0);

                a = 255;

                break;

            case 0x88:

                r = ((i & 1) ? 43 : 0) + ((i & 0x10) ? 85 : 0);

                g = ((i & 2) ? 43 : 0) + ((i & 0x20) ? 85 : 0);

                b = ((i & 4) ? 43 : 0) + ((i & 0x40) ? 85 : 0);

                a = 255;

                break;

            }

        }

        default_clut.clut256[i] = RGBA(r, g, b, a);

    }

    return 0;

}

static av_cold int dvbsub_close_decoder(AVCodecContext *avctx)

{

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

    DVBSubRegionDisplay *display;

    delete_state(ctx);

    while (ctx->display_list) {

        display = ctx->display_list;

        ctx->display_list = display->next;

        av_free(display);

    }

    return 0;

}

static int dvbsub_read_2bit_string(uint8_t *destbuf, int dbuf_len,

                                   const uint8_t **srcbuf, int buf_size,

                                   int non_mod, uint8_t *map_table)

{

    GetBitContext gb;

    int bits;

    int run_length;

    int pixels_read = 0;

    init_get_bits(&gb, *srcbuf, buf_size << 3);

    while (get_bits_count(&gb) < buf_size << 3 && pixels_read < dbuf_len) {

        bits = get_bits(&gb, 2);

        if (bits) {

            if (non_mod != 1 || bits != 1) {

                if (map_table)

                    *destbuf++ = map_table[bits];

                else

                    *destbuf++ = bits;

            }

            pixels_read++;

        } else {

            bits = get_bits1(&gb);

            if (bits == 1) {

                run_length = get_bits(&gb, 3) + 3;

                bits = get_bits(&gb, 2);

                if (non_mod == 1 && bits == 1)

                    pixels_read += run_length;

                else {

                    if (map_table)

                        bits = map_table[bits];

                    while (run_length-- > 0 && pixels_read < dbuf_len) {

                        *destbuf++ = bits;

                        pixels_read++;

                    }

                }

            } else {

                bits = get_bits1(&gb);

                if (bits == 0) {

                    bits = get_bits(&gb, 2);

                    if (bits == 2) {

                        run_length = get_bits(&gb, 4) + 12;

                        bits = get_bits(&gb, 2);

                        if (non_mod == 1 && bits == 1)

                            pixels_read += run_length;

                        else {

                            if (map_table)

                                bits = map_table[bits];

                            while (run_length-- > 0 && pixels_read < dbuf_len) {

                                *destbuf++ = bits;

                                pixels_read++;

                            }

                        }

                    } else if (bits == 3) {

                        run_length = get_bits(&gb, 8) + 29;

                        bits = get_bits(&gb, 2);

                        if (non_mod == 1 && bits == 1)

                            pixels_read += run_length;

                        else {

                            if (map_table)

                                bits = map_table[bits];

                            while (run_length-- > 0 && pixels_read < dbuf_len) {

                                *destbuf++ = bits;

                                pixels_read++;

                            }

                        }

                    } else if (bits == 1) {

                        pixels_read += 2;

                        if (map_table)

                            bits = map_table[0];

                        else

                            bits = 0;

                        if (pixels_read <= dbuf_len) {

                            *destbuf++ = bits;

                            *destbuf++ = bits;

                        }

                    } else {

                        (*srcbuf) += (get_bits_count(&gb) + 7) >> 3;

                        return pixels_read;

                    }

                } else {

                    if (map_table)

                        bits = map_table[0];

                    else

                        bits = 0;

                    *destbuf++ = bits;

                    pixels_read++;

                }

            }

        }

    }

    if (get_bits(&gb, 6))

        av_log(0, AV_LOG_ERROR, "DVBSub error: line overflow\n");

    (*srcbuf) += (get_bits_count(&gb) + 7) >> 3;

    return pixels_read;

}

static int dvbsub_read_4bit_string(uint8_t *destbuf, int dbuf_len,

                                   const uint8_t **srcbuf, int buf_size,

                                   int non_mod, uint8_t *map_table)

{

    GetBitContext gb;

    int bits;

    int run_length;

    int pixels_read = 0;

    init_get_bits(&gb, *srcbuf, buf_size << 3);

    while (get_bits_count(&gb) < buf_size << 3 && pixels_read < dbuf_len) {

        bits = get_bits(&gb, 4);

        if (bits) {

            if (non_mod != 1 || bits != 1) {

                if (map_table)

                    *destbuf++ = map_table[bits];

                else

                    *destbuf++ = bits;

            }

            pixels_read++;

        } else {

            bits = get_bits1(&gb);

            if (bits == 0) {

                run_length = get_bits(&gb, 3);

                if (run_length == 0) {

                    (*srcbuf) += (get_bits_count(&gb) + 7) >> 3;

                    return pixels_read;

                }

                run_length += 2;

                if (map_table)

                    bits = map_table[0];

                else

                    bits = 0;

                while (run_length-- > 0 && pixels_read < dbuf_len) {

                    *destbuf++ = bits;

                    pixels_read++;

                }

            } else {

                bits = get_bits1(&gb);

                if (bits == 0) {

                    run_length = get_bits(&gb, 2) + 4;

                    bits = get_bits(&gb, 4);

                    if (non_mod == 1 && bits == 1)

                        pixels_read += run_length;

                    else {

                        if (map_table)

                            bits = map_table[bits];

                        while (run_length-- > 0 && pixels_read < dbuf_len) {

                            *destbuf++ = bits;

                            pixels_read++;

                        }

                    }

                } else {

                    bits = get_bits(&gb, 2);

                    if (bits == 2) {

                        run_length = get_bits(&gb, 4) + 9;

                        bits = get_bits(&gb, 4);

                        if (non_mod == 1 && bits == 1)

                            pixels_read += run_length;

                        else {

                            if (map_table)

                                bits = map_table[bits];

                            while (run_length-- > 0 && pixels_read < dbuf_len) {

                                *destbuf++ = bits;

                                pixels_read++;

                            }

                        }

                    } else if (bits == 3) {

                        run_length = get_bits(&gb, 8) + 25;

                        bits = get_bits(&gb, 4);

                        if (non_mod == 1 && bits == 1)

                            pixels_read += run_length;

                        else {

                            if (map_table)

                                bits = map_table[bits];

                            while (run_length-- > 0 && pixels_read < dbuf_len) {

                                *destbuf++ = bits;

                                pixels_read++;

                            }

                        }

                    } else if (bits == 1) {

                        pixels_read += 2;

                        if (map_table)

                            bits = map_table[0];

                        else

                            bits = 0;

                        if (pixels_read <= dbuf_len) {

                            *destbuf++ = bits;

                            *destbuf++ = bits;

                        }

                    } else {

                        if (map_table)

                            bits = map_table[0];

                        else

                            bits = 0;

                        *destbuf++ = bits;

                        pixels_read ++;

                    }

                }

            }

        }

    }

    if (get_bits(&gb, 8))

        av_log(0, AV_LOG_ERROR, "DVBSub error: line overflow\n");

    (*srcbuf) += (get_bits_count(&gb) + 7) >> 3;

    return pixels_read;

}

static int dvbsub_read_8bit_string(uint8_t *destbuf, int dbuf_len,

                                    const uint8_t **srcbuf, int buf_size,

                                    int non_mod, uint8_t *map_table)

{

    const uint8_t *sbuf_end = (*srcbuf) + buf_size;

    int bits;

    int run_length;

    int pixels_read = 0;

    while (*srcbuf < sbuf_end && pixels_read < dbuf_len) {

        bits = *(*srcbuf)++;

        if (bits) {

            if (non_mod != 1 || bits != 1) {

                if (map_table)

                    *destbuf++ = map_table[bits];

                else

                    *destbuf++ = bits;

            }

            pixels_read++;

        } else {

            bits = *(*srcbuf)++;

            run_length = bits & 0x7f;

            if ((bits & 0x80) == 0) {

                if (run_length == 0) {

                    return pixels_read;

                }

                if (map_table)

                    bits = map_table[0];

                else

                    bits = 0;

                while (run_length-- > 0 && pixels_read < dbuf_len) {

                    *destbuf++ = bits;

                    pixels_read++;

                }

            } else {

                bits = *(*srcbuf)++;

                if (non_mod == 1 && bits == 1)

                    pixels_read += run_length;

                if (map_table)

                    bits = map_table[bits];

                else while (run_length-- > 0 && pixels_read < dbuf_len) {

                    *destbuf++ = bits;

                    pixels_read++;

                }

            }

        }

    }

    if (*(*srcbuf)++)

        av_log(0, AV_LOG_ERROR, "DVBSub error: line overflow\n");

    return pixels_read;

}

static void dvbsub_parse_pixel_data_block(AVCodecContext *avctx, DVBSubObjectDisplay *display,

                                          const uint8_t *buf, int buf_size, int top_bottom, int non_mod)

{

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

    DVBSubRegion *region = get_region(ctx, display->region_id);

    const uint8_t *buf_end = buf + buf_size;

    uint8_t *pbuf;

    int x_pos, y_pos;

    int i;

    uint8_t map2to4[] = { 0x0,  0x7,  0x8,  0xf};

    uint8_t map2to8[] = {0x00, 0x77, 0x88, 0xff};

    uint8_t map4to8[] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,

                         0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff};

    uint8_t *map_table;

    dprintf(avctx, "DVB pixel block size %d, %s field:\n", buf_size,

            top_bottom ? "bottom" : "top");

#ifdef DEBUG_PACKET_CONTENTS

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

        if (i % 16 == 0)

            av_log(avctx, AV_LOG_INFO, "0x%08p: ", buf+i);

        av_log(avctx, AV_LOG_INFO, "%02x ", buf[i]);

        if (i % 16 == 15)

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

    }

    if (i % 16)

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

#endif

    if (region == 0)

        return;

    pbuf = region->pbuf;

    x_pos = display->x_pos;

    y_pos = display->y_pos;

    if ((y_pos & 1) != top_bottom)

        y_pos++;

    while (buf < buf_end) {

        if (x_pos > region->width || y_pos > region->height) {

            av_log(avctx, AV_LOG_ERROR, "Invalid object location!\n");

            return;

        }

        switch (*buf++) {

        case 0x10:

            if (region->depth == 8)

                map_table = map2to8;

            else if (region->depth == 4)

                map_table = map2to4;

            else

                map_table = NULL;

            x_pos += dvbsub_read_2bit_string(pbuf + (y_pos * region->width) + x_pos,

                                                region->width - x_pos, &buf, buf_size,

                                                non_mod, map_table);

            break;

        case 0x11:

            if (region->depth < 4) {

                av_log(avctx, AV_LOG_ERROR, "4-bit pixel string in %d-bit region!\n", region->depth);

                return;

            }

            if (region->depth == 8)

                map_table = map4to8;

            else

                map_table = NULL;

            x_pos += dvbsub_read_4bit_string(pbuf + (y_pos * region->width) + x_pos,

                                                region->width - x_pos, &buf, buf_size,

                                                non_mod, map_table);

            break;

        case 0x12:

            if (region->depth < 8) {

                av_log(avctx, AV_LOG_ERROR, "8-bit pixel string in %d-bit region!\n", region->depth);

                return;

            }

            x_pos += dvbsub_read_8bit_string(pbuf + (y_pos * region->width) + x_pos,

                                                region->width - x_pos, &buf, buf_size,

                                                non_mod, NULL);

            break;

        case 0x20:

            map2to4[0] = (*buf) >> 4;

            map2to4[1] = (*buf++) & 0xf;

            map2to4[2] = (*buf) >> 4;

            map2to4[3] = (*buf++) & 0xf;

            break;

        case 0x21:

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

                map2to8[i] = *buf++;

            break;

        case 0x22:

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

                map4to8[i] = *buf++;

            break;

        case 0xf0:

            x_pos = display->x_pos;

            y_pos += 2;

            break;

        default:

            av_log(avctx, AV_LOG_INFO, "Unknown/unsupported pixel block 0x%x\n", *(buf-1));

        }

    }

}

static void dvbsub_parse_object_segment(AVCodecContext *avctx,

                                        const uint8_t *buf, int buf_size)

{

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

    const uint8_t *buf_end = buf + buf_size;

    const uint8_t *block;

    int object_id;

    DVBSubObject *object;

    DVBSubObjectDisplay *display;

    int top_field_len, bottom_field_len;

    int coding_method, non_modifying_color;

    object_id = AV_RB16(buf);

    buf += 2;

    object = get_object(ctx, object_id);

    if (!object)

        return;

    coding_method = ((*buf) >> 2) & 3;

    non_modifying_color = ((*buf++) >> 1) & 1;

    if (coding_method == 0) {

        top_field_len = AV_RB16(buf);

        buf += 2;

        bottom_field_len = AV_RB16(buf);

        buf += 2;

        if (buf + top_field_len + bottom_field_len > buf_end) {

            av_log(avctx, AV_LOG_ERROR, "Field data size too large\n");

            return;

        }

        for (display = object->display_list; display; display = display->object_list_next) {

            block = buf;

            dvbsub_parse_pixel_data_block(avctx, display, block, top_field_len, 0,

                                            non_modifying_color);

            if (bottom_field_len > 0)

                block = buf + top_field_len;

            else

                bottom_field_len = top_field_len;

            dvbsub_parse_pixel_data_block(avctx, display, block, bottom_field_len, 1,

                                            non_modifying_color);

        }

/*  } else if (coding_method == 1) {*/

    } else {

        av_log(avctx, AV_LOG_ERROR, "Unknown object coding %d\n", coding_method);

    }

}

static void dvbsub_parse_clut_segment(AVCodecContext *avctx,

                                        const uint8_t *buf, int buf_size)

{

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

    const uint8_t *buf_end = buf + buf_size;

    int clut_id;

    DVBSubCLUT *clut;

    int entry_id, depth , full_range;

    int y, cr, cb, alpha;

    int r, g, b, r_add, g_add, b_add;

#ifdef DEBUG_PACKET_CONTENTS

    int i;

    av_log(avctx, AV_LOG_INFO, "DVB clut packet:\n");

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

        av_log(avctx, AV_LOG_INFO, "%02x ", buf[i]);

        if (i % 16 == 15)

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

    }

    if (i % 16)

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

#endif

    clut_id = *buf++;

    buf += 1;

    clut = get_clut(ctx, clut_id);

    if (!clut) {

        clut = av_malloc(sizeof(DVBSubCLUT));

        memcpy(clut, &default_clut, sizeof(DVBSubCLUT));

        clut->id = clut_id;

        clut->next = ctx->clut_list;

        ctx->clut_list = clut;

    }

    while (buf + 4 < buf_end) {

        entry_id = *buf++;

        depth = (*buf) & 0xe0;

        if (depth == 0) {

            av_log(avctx, AV_LOG_ERROR, "Invalid clut depth 0x%x!\n", *buf);

            return;

        }

        full_range = (*buf++) & 1;

        if (full_range) {