Libav 0.7.1
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00001 /* 00002 * PGS subtitle decoder 00003 * Copyright (c) 2009 Stephen Backway 00004 * 00005 * This file is part of Libav. 00006 * 00007 * Libav is free software; you can redistribute it and/or 00008 * modify it under the terms of the GNU Lesser General Public 00009 * License as published by the Free Software Foundation; either 00010 * version 2.1 of the License, or (at your option) any later version. 00011 * 00012 * Libav is distributed in the hope that it will be useful, 00013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00015 * Lesser General Public License for more details. 00016 * 00017 * You should have received a copy of the GNU Lesser General Public 00018 * License along with Libav; if not, write to the Free Software 00019 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 00020 */ 00021 00027 #include "avcodec.h" 00028 #include "dsputil.h" 00029 #include "bytestream.h" 00030 #include "libavutil/colorspace.h" 00031 #include "libavutil/imgutils.h" 00032 00033 #define RGBA(r,g,b,a) (((a) << 24) | ((r) << 16) | ((g) << 8) | (b)) 00034 00035 enum SegmentType { 00036 PALETTE_SEGMENT = 0x14, 00037 PICTURE_SEGMENT = 0x15, 00038 PRESENTATION_SEGMENT = 0x16, 00039 WINDOW_SEGMENT = 0x17, 00040 DISPLAY_SEGMENT = 0x80, 00041 }; 00042 00043 typedef struct PGSSubPresentation { 00044 int x; 00045 int y; 00046 int id_number; 00047 int object_number; 00048 } PGSSubPresentation; 00049 00050 typedef struct PGSSubPicture { 00051 int w; 00052 int h; 00053 uint8_t *rle; 00054 unsigned int rle_buffer_size, rle_data_len; 00055 unsigned int rle_remaining_len; 00056 } PGSSubPicture; 00057 00058 typedef struct PGSSubContext { 00059 PGSSubPresentation presentation; 00060 uint32_t clut[256]; 00061 PGSSubPicture picture; 00062 } PGSSubContext; 00063 00064 static av_cold int init_decoder(AVCodecContext *avctx) 00065 { 00066 avctx->pix_fmt = PIX_FMT_PAL8; 00067 00068 return 0; 00069 } 00070 00071 static av_cold int close_decoder(AVCodecContext *avctx) 00072 { 00073 PGSSubContext *ctx = avctx->priv_data; 00074 00075 av_freep(&ctx->picture.rle); 00076 ctx->picture.rle_buffer_size = 0; 00077 00078 return 0; 00079 } 00080 00091 static int decode_rle(AVCodecContext *avctx, AVSubtitle *sub, 00092 const uint8_t *buf, unsigned int buf_size) 00093 { 00094 const uint8_t *rle_bitmap_end; 00095 int pixel_count, line_count; 00096 00097 rle_bitmap_end = buf + buf_size; 00098 00099 sub->rects[0]->pict.data[0] = av_malloc(sub->rects[0]->w * sub->rects[0]->h); 00100 00101 if (!sub->rects[0]->pict.data[0]) 00102 return -1; 00103 00104 pixel_count = 0; 00105 line_count = 0; 00106 00107 while (buf < rle_bitmap_end && line_count < sub->rects[0]->h) { 00108 uint8_t flags, color; 00109 int run; 00110 00111 color = bytestream_get_byte(&buf); 00112 run = 1; 00113 00114 if (color == 0x00) { 00115 flags = bytestream_get_byte(&buf); 00116 run = flags & 0x3f; 00117 if (flags & 0x40) 00118 run = (run << 8) + bytestream_get_byte(&buf); 00119 color = flags & 0x80 ? bytestream_get_byte(&buf) : 0; 00120 } 00121 00122 if (run > 0 && pixel_count + run <= sub->rects[0]->w * sub->rects[0]->h) { 00123 memset(sub->rects[0]->pict.data[0] + pixel_count, color, run); 00124 pixel_count += run; 00125 } else if (!run) { 00126 /* 00127 * New Line. Check if correct pixels decoded, if not display warning 00128 * and adjust bitmap pointer to correct new line position. 00129 */ 00130 if (pixel_count % sub->rects[0]->w > 0) 00131 av_log(avctx, AV_LOG_ERROR, "Decoded %d pixels, when line should be %d pixels\n", 00132 pixel_count % sub->rects[0]->w, sub->rects[0]->w); 00133 line_count++; 00134 } 00135 } 00136 00137 if (pixel_count < sub->rects[0]->w * sub->rects[0]->h) { 00138 av_log(avctx, AV_LOG_ERROR, "Insufficient RLE data for subtitle\n"); 00139 return -1; 00140 } 00141 00142 av_dlog(avctx, "Pixel Count = %d, Area = %d\n", pixel_count, sub->rects[0]->w * sub->rects[0]->h); 00143 00144 return 0; 00145 } 00146 00158 static int parse_picture_segment(AVCodecContext *avctx, 00159 const uint8_t *buf, int buf_size) 00160 { 00161 PGSSubContext *ctx = avctx->priv_data; 00162 00163 uint8_t sequence_desc; 00164 unsigned int rle_bitmap_len, width, height; 00165 00166 if (buf_size <= 4) 00167 return -1; 00168 buf_size -= 4; 00169 00170 /* skip 3 unknown bytes: Object ID (2 bytes), Version Number */ 00171 buf += 3; 00172 00173 /* Read the Sequence Description to determine if start of RLE data or appended to previous RLE */ 00174 sequence_desc = bytestream_get_byte(&buf); 00175 00176 if (!(sequence_desc & 0x80)) { 00177 /* Additional RLE data */ 00178 if (buf_size > ctx->picture.rle_remaining_len) 00179 return -1; 00180 00181 memcpy(ctx->picture.rle + ctx->picture.rle_data_len, buf, buf_size); 00182 ctx->picture.rle_data_len += buf_size; 00183 ctx->picture.rle_remaining_len -= buf_size; 00184 00185 return 0; 00186 } 00187 00188 if (buf_size <= 7) 00189 return -1; 00190 buf_size -= 7; 00191 00192 /* Decode rle bitmap length, stored size includes width/height data */ 00193 rle_bitmap_len = bytestream_get_be24(&buf) - 2*2; 00194 00195 /* Get bitmap dimensions from data */ 00196 width = bytestream_get_be16(&buf); 00197 height = bytestream_get_be16(&buf); 00198 00199 /* Make sure the bitmap is not too large */ 00200 if (avctx->width < width || avctx->height < height) { 00201 av_log(avctx, AV_LOG_ERROR, "Bitmap dimensions larger then video.\n"); 00202 return -1; 00203 } 00204 00205 ctx->picture.w = width; 00206 ctx->picture.h = height; 00207 00208 av_fast_malloc(&ctx->picture.rle, &ctx->picture.rle_buffer_size, rle_bitmap_len); 00209 00210 if (!ctx->picture.rle) 00211 return -1; 00212 00213 memcpy(ctx->picture.rle, buf, buf_size); 00214 ctx->picture.rle_data_len = buf_size; 00215 ctx->picture.rle_remaining_len = rle_bitmap_len - buf_size; 00216 00217 return 0; 00218 } 00219 00230 static void parse_palette_segment(AVCodecContext *avctx, 00231 const uint8_t *buf, int buf_size) 00232 { 00233 PGSSubContext *ctx = avctx->priv_data; 00234 00235 const uint8_t *buf_end = buf + buf_size; 00236 const uint8_t *cm = ff_cropTbl + MAX_NEG_CROP; 00237 int color_id; 00238 int y, cb, cr, alpha; 00239 int r, g, b, r_add, g_add, b_add; 00240 00241 /* Skip two null bytes */ 00242 buf += 2; 00243 00244 while (buf < buf_end) { 00245 color_id = bytestream_get_byte(&buf); 00246 y = bytestream_get_byte(&buf); 00247 cr = bytestream_get_byte(&buf); 00248 cb = bytestream_get_byte(&buf); 00249 alpha = bytestream_get_byte(&buf); 00250 00251 YUV_TO_RGB1(cb, cr); 00252 YUV_TO_RGB2(r, g, b, y); 00253 00254 av_dlog(avctx, "Color %d := (%d,%d,%d,%d)\n", color_id, r, g, b, alpha); 00255 00256 /* Store color in palette */ 00257 ctx->clut[color_id] = RGBA(r,g,b,alpha); 00258 } 00259 } 00260 00273 static void parse_presentation_segment(AVCodecContext *avctx, 00274 const uint8_t *buf, int buf_size) 00275 { 00276 PGSSubContext *ctx = avctx->priv_data; 00277 00278 int x, y; 00279 00280 int w = bytestream_get_be16(&buf); 00281 int h = bytestream_get_be16(&buf); 00282 00283 av_dlog(avctx, "Video Dimensions %dx%d\n", 00284 w, h); 00285 if (av_image_check_size(w, h, 0, avctx) >= 0) 00286 avcodec_set_dimensions(avctx, w, h); 00287 00288 /* Skip 1 bytes of unknown, frame rate? */ 00289 buf++; 00290 00291 ctx->presentation.id_number = bytestream_get_be16(&buf); 00292 00293 /* 00294 * Skip 3 bytes of unknown: 00295 * state 00296 * palette_update_flag (0x80), 00297 * palette_id_to_use, 00298 */ 00299 buf += 3; 00300 00301 ctx->presentation.object_number = bytestream_get_byte(&buf); 00302 if (!ctx->presentation.object_number) 00303 return; 00304 00305 /* 00306 * Skip 4 bytes of unknown: 00307 * object_id_ref (2 bytes), 00308 * window_id_ref, 00309 * composition_flag (0x80 - object cropped, 0x40 - object forced) 00310 */ 00311 buf += 4; 00312 00313 x = bytestream_get_be16(&buf); 00314 y = bytestream_get_be16(&buf); 00315 00316 /* TODO If cropping, cropping_x, cropping_y, cropping_width, cropping_height (all 2 bytes).*/ 00317 00318 av_dlog(avctx, "Subtitle Placement x=%d, y=%d\n", x, y); 00319 00320 if (x > avctx->width || y > avctx->height) { 00321 av_log(avctx, AV_LOG_ERROR, "Subtitle out of video bounds. x = %d, y = %d, video width = %d, video height = %d.\n", 00322 x, y, avctx->width, avctx->height); 00323 x = 0; y = 0; 00324 } 00325 00326 /* Fill in dimensions */ 00327 ctx->presentation.x = x; 00328 ctx->presentation.y = y; 00329 } 00330 00346 static int display_end_segment(AVCodecContext *avctx, void *data, 00347 const uint8_t *buf, int buf_size) 00348 { 00349 AVSubtitle *sub = data; 00350 PGSSubContext *ctx = avctx->priv_data; 00351 00352 /* 00353 * The end display time is a timeout value and is only reached 00354 * if the next subtitle is later then timeout or subtitle has 00355 * not been cleared by a subsequent empty display command. 00356 */ 00357 00358 memset(sub, 0, sizeof(*sub)); 00359 // Blank if last object_number was 0. 00360 // Note that this may be wrong for more complex subtitles. 00361 if (!ctx->presentation.object_number) 00362 return 1; 00363 sub->start_display_time = 0; 00364 sub->end_display_time = 20000; 00365 sub->format = 0; 00366 00367 sub->rects = av_mallocz(sizeof(*sub->rects)); 00368 sub->rects[0] = av_mallocz(sizeof(*sub->rects[0])); 00369 sub->num_rects = 1; 00370 00371 sub->rects[0]->x = ctx->presentation.x; 00372 sub->rects[0]->y = ctx->presentation.y; 00373 sub->rects[0]->w = ctx->picture.w; 00374 sub->rects[0]->h = ctx->picture.h; 00375 sub->rects[0]->type = SUBTITLE_BITMAP; 00376 00377 /* Process bitmap */ 00378 sub->rects[0]->pict.linesize[0] = ctx->picture.w; 00379 00380 if (ctx->picture.rle) { 00381 if (ctx->picture.rle_remaining_len) 00382 av_log(avctx, AV_LOG_ERROR, "RLE data length %u is %u bytes shorter than expected\n", 00383 ctx->picture.rle_data_len, ctx->picture.rle_remaining_len); 00384 if(decode_rle(avctx, sub, ctx->picture.rle, ctx->picture.rle_data_len) < 0) 00385 return 0; 00386 } 00387 /* Allocate memory for colors */ 00388 sub->rects[0]->nb_colors = 256; 00389 sub->rects[0]->pict.data[1] = av_mallocz(AVPALETTE_SIZE); 00390 00391 memcpy(sub->rects[0]->pict.data[1], ctx->clut, sub->rects[0]->nb_colors * sizeof(uint32_t)); 00392 00393 return 1; 00394 } 00395 00396 static int decode(AVCodecContext *avctx, void *data, int *data_size, 00397 AVPacket *avpkt) 00398 { 00399 const uint8_t *buf = avpkt->data; 00400 int buf_size = avpkt->size; 00401 00402 const uint8_t *buf_end; 00403 uint8_t segment_type; 00404 int segment_length; 00405 int i; 00406 00407 av_dlog(avctx, "PGS sub packet:\n"); 00408 00409 for (i = 0; i < buf_size; i++) { 00410 av_dlog(avctx, "%02x ", buf[i]); 00411 if (i % 16 == 15) 00412 av_dlog(avctx, "\n"); 00413 } 00414 00415 if (i & 15) 00416 av_dlog(avctx, "\n"); 00417 00418 *data_size = 0; 00419 00420 /* Ensure that we have received at a least a segment code and segment length */ 00421 if (buf_size < 3) 00422 return -1; 00423 00424 buf_end = buf + buf_size; 00425 00426 /* Step through buffer to identify segments */ 00427 while (buf < buf_end) { 00428 segment_type = bytestream_get_byte(&buf); 00429 segment_length = bytestream_get_be16(&buf); 00430 00431 av_dlog(avctx, "Segment Length %d, Segment Type %x\n", segment_length, segment_type); 00432 00433 if (segment_type != DISPLAY_SEGMENT && segment_length > buf_end - buf) 00434 break; 00435 00436 switch (segment_type) { 00437 case PALETTE_SEGMENT: 00438 parse_palette_segment(avctx, buf, segment_length); 00439 break; 00440 case PICTURE_SEGMENT: 00441 parse_picture_segment(avctx, buf, segment_length); 00442 break; 00443 case PRESENTATION_SEGMENT: 00444 parse_presentation_segment(avctx, buf, segment_length); 00445 break; 00446 case WINDOW_SEGMENT: 00447 /* 00448 * Window Segment Structure (No new information provided): 00449 * 2 bytes: Unkown, 00450 * 2 bytes: X position of subtitle, 00451 * 2 bytes: Y position of subtitle, 00452 * 2 bytes: Width of subtitle, 00453 * 2 bytes: Height of subtitle. 00454 */ 00455 break; 00456 case DISPLAY_SEGMENT: 00457 *data_size = display_end_segment(avctx, data, buf, segment_length); 00458 break; 00459 default: 00460 av_log(avctx, AV_LOG_ERROR, "Unknown subtitle segment type 0x%x, length %d\n", 00461 segment_type, segment_length); 00462 break; 00463 } 00464 00465 buf += segment_length; 00466 } 00467 00468 return buf_size; 00469 } 00470 00471 AVCodec ff_pgssub_decoder = { 00472 "pgssub", 00473 AVMEDIA_TYPE_SUBTITLE, 00474 CODEC_ID_HDMV_PGS_SUBTITLE, 00475 sizeof(PGSSubContext), 00476 init_decoder, 00477 NULL, 00478 close_decoder, 00479 decode, 00480 .long_name = NULL_IF_CONFIG_SMALL("HDMV Presentation Graphic Stream subtitles"), 00481 };