/* * PGS subtitle decoder * Copyright (c) 2009 Stephen Backway * * 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 */ /** * @file * PGS subtitle decoder */ #include "avcodec.h" #include "dsputil.h" #include "bytestream.h" #include "libavutil/colorspace.h" #include "libavutil/imgutils.h" #include "libavutil/opt.h" #define RGBA(r,g,b,a) (((a) << 24) | ((r) << 16) | ((g) << 8) | (b)) enum SegmentType { PALETTE_SEGMENT = 0x14, PICTURE_SEGMENT = 0x15, PRESENTATION_SEGMENT = 0x16, WINDOW_SEGMENT = 0x17, DISPLAY_SEGMENT = 0x80, }; typedef struct PGSSubPictureReference { int x; int y; int picture_id; int composition; } PGSSubPictureReference; typedef struct PGSSubPresentation { int id_number; int object_count; PGSSubPictureReference *objects; } PGSSubPresentation; typedef struct PGSSubPicture { int w; int h; uint8_t *rle; unsigned int rle_buffer_size, rle_data_len; unsigned int rle_remaining_len; } PGSSubPicture; typedef struct PGSSubContext { AVClass *class; PGSSubPresentation presentation; uint32_t clut[256]; PGSSubPicture pictures[UINT16_MAX]; int64_t pts; int forced_subs_only; } PGSSubContext; static av_cold int init_decoder(AVCodecContext *avctx) { avctx->pix_fmt = PIX_FMT_PAL8; return 0; } static av_cold int close_decoder(AVCodecContext *avctx) { uint16_t picture; PGSSubContext *ctx = avctx->priv_data; av_freep(&ctx->presentation.objects); ctx->presentation.object_count = 0; for (picture = 0; picture < UINT16_MAX; ++picture) { av_freep(&ctx->pictures[picture].rle); ctx->pictures[picture].rle_buffer_size = 0; } return 0; } /** * Decode the RLE data. * * The subtitle is stored as an Run Length Encoded image. * * @param avctx contains the current codec context * @param sub pointer to the processed subtitle data * @param buf pointer to the RLE data to process * @param buf_size size of the RLE data to process */ static int decode_rle(AVCodecContext *avctx, AVSubtitle *sub, int rect, const uint8_t *buf, unsigned int buf_size) { const uint8_t *rle_bitmap_end; int pixel_count, line_count; rle_bitmap_end = buf + buf_size; sub->rects[rect]->pict.data[0] = av_malloc(sub->rects[rect]->w * sub->rects[rect]->h); if (!sub->rects[rect]->pict.data[0]) return -1; pixel_count = 0; line_count = 0; while (buf < rle_bitmap_end && line_count < sub->rects[rect]->h) { uint8_t flags, color; int run; color = bytestream_get_byte(&buf); run = 1; if (color == 0x00) { flags = bytestream_get_byte(&buf); run = flags & 0x3f; if (flags & 0x40) run = (run << 8) + bytestream_get_byte(&buf); color = flags & 0x80 ? bytestream_get_byte(&buf) : 0; } if (run > 0 && pixel_count + run <= sub->rects[rect]->w * sub->rects[rect]->h) { memset(sub->rects[rect]->pict.data[0] + pixel_count, color, run); pixel_count += run; } else if (!run) { /* * New Line. Check if correct pixels decoded, if not display warning * and adjust bitmap pointer to correct new line position. */ if (pixel_count % sub->rects[rect]->w > 0) av_log(avctx, AV_LOG_ERROR, "Decoded %d pixels, when line should be %d pixels\n", pixel_count % sub->rects[rect]->w, sub->rects[rect]->w); line_count++; } } if (pixel_count < sub->rects[rect]->w * sub->rects[rect]->h) { av_log(avctx, AV_LOG_ERROR, "Insufficient RLE data for subtitle\n"); return -1; } av_dlog(avctx, "Pixel Count = %d, Area = %d\n", pixel_count, sub->rects[rect]->w * sub->rects[rect]->h); return 0; } /** * Parse the picture segment packet. * * The picture segment contains details on the sequence id, * width, height and Run Length Encoded (RLE) bitmap data. * * @param avctx contains the current codec context * @param buf pointer to the packet to process * @param buf_size size of packet to process * @todo TODO: Enable support for RLE data over multiple packets */ static int parse_picture_segment(AVCodecContext *avctx, const uint8_t *buf, int buf_size) { PGSSubContext *ctx = avctx->priv_data; uint8_t sequence_desc; unsigned int rle_bitmap_len, width, height; uint16_t picture_id; if (buf_size <= 4) return -1; buf_size -= 4; picture_id = bytestream_get_be16(&buf); /* skip 1 unknown byte: Version Number */ buf++; /* Read the Sequence Description to determine if start of RLE data or appended to previous RLE */ sequence_desc = bytestream_get_byte(&buf); if (!(sequence_desc & 0x80)) { /* Additional RLE data */ if (buf_size > ctx->pictures[picture_id].rle_remaining_len) return -1; memcpy(ctx->pictures[picture_id].rle + ctx->pictures[picture_id].rle_data_len, buf, buf_size); ctx->pictures[picture_id].rle_data_len += buf_size; ctx->pictures[picture_id].rle_remaining_len -= buf_size; return 0; } if (buf_size <= 7) return -1; buf_size -= 7; /* Decode rle bitmap length, stored size includes width/height data */ rle_bitmap_len = bytestream_get_be24(&buf) - 2*2; /* Get bitmap dimensions from data */ width = bytestream_get_be16(&buf); height = bytestream_get_be16(&buf); /* Make sure the bitmap is not too large */ if (avctx->width < width || avctx->height < height) { av_log(avctx, AV_LOG_ERROR, "Bitmap dimensions larger than video.\n"); return -1; } if (buf_size > rle_bitmap_len) { av_log(avctx, AV_LOG_ERROR, "too much RLE data\n"); return AVERROR_INVALIDDATA; } ctx->pictures[picture_id].w = width; ctx->pictures[picture_id].h = height; av_fast_malloc(&ctx->pictures[picture_id].rle, &ctx->pictures[picture_id].rle_buffer_size, rle_bitmap_len); if (!ctx->pictures[picture_id].rle) return -1; memcpy(ctx->pictures[picture_id].rle, buf, buf_size); ctx->pictures[picture_id].rle_data_len = buf_size; ctx->pictures[picture_id].rle_remaining_len = rle_bitmap_len - buf_size; return 0; } /** * Parse the palette segment packet. * * The palette segment contains details of the palette, * a maximum of 256 colors can be defined. * * @param avctx contains the current codec context * @param buf pointer to the packet to process * @param buf_size size of packet to process */ static void parse_palette_segment(AVCodecContext *avctx, const uint8_t *buf, int buf_size) { PGSSubContext *ctx = avctx->priv_data; const uint8_t *buf_end = buf + buf_size; const uint8_t *cm = ff_cropTbl + MAX_NEG_CROP; int color_id; int y, cb, cr, alpha; int r, g, b, r_add, g_add, b_add; /* Skip two null bytes */ buf += 2; while (buf < buf_end) { color_id = bytestream_get_byte(&buf); y = bytestream_get_byte(&buf); cr = bytestream_get_byte(&buf); cb = bytestream_get_byte(&buf); alpha = bytestream_get_byte(&buf); YUV_TO_RGB1(cb, cr); YUV_TO_RGB2(r, g, b, y); av_dlog(avctx, "Color %d := (%d,%d,%d,%d)\n", color_id, r, g, b, alpha); /* Store color in palette */ ctx->clut[color_id] = RGBA(r,g,b,alpha); } } /** * Parse the presentation segment packet. * * The presentation segment contains details on the video * width, video height, x & y subtitle position. * * @param avctx contains the current codec context * @param buf pointer to the packet to process * @param buf_size size of packet to process * @todo TODO: Implement cropping */ static void parse_presentation_segment(AVCodecContext *avctx, const uint8_t *buf, int buf_size) { PGSSubContext *ctx = avctx->priv_data; int w = bytestream_get_be16(&buf); int h = bytestream_get_be16(&buf); uint16_t object_index; av_dlog(avctx, "Video Dimensions %dx%d\n", w, h); if (av_image_check_size(w, h, 0, avctx) >= 0) avcodec_set_dimensions(avctx, w, h); /* Skip 1 bytes of unknown, frame rate? */ buf++; ctx->presentation.id_number = bytestream_get_be16(&buf); /* * Skip 3 bytes of unknown: * state * palette_update_flag (0x80), * palette_id_to_use, */ buf += 3; ctx->presentation.object_count = bytestream_get_byte(&buf); if (!ctx->presentation.object_count) return; /* Verify that enough bytes are remaining for all of the objects. */ buf_size -= 11; if (buf_size < ctx->presentation.object_count * 8) { ctx->presentation.object_count = 0; return; } av_freep(&ctx->presentation.objects); ctx->presentation.objects = av_malloc(sizeof(PGSSubPictureReference) * ctx->presentation.object_count); if (!ctx->presentation.objects) { ctx->presentation.object_count = 0; return; } for (object_index = 0; object_index < ctx->presentation.object_count; ++object_index) { PGSSubPictureReference *reference = &ctx->presentation.objects[object_index]; reference->picture_id = bytestream_get_be16(&buf); /* Skip window_id_ref */ buf++; /* composition_flag (0x80 - object cropped, 0x40 - object forced) */ reference->composition = bytestream_get_byte(&buf); reference->x = bytestream_get_be16(&buf); reference->y = bytestream_get_be16(&buf); /* TODO If cropping, cropping_x, cropping_y, cropping_width, cropping_height (all 2 bytes).*/ av_dlog(avctx, "Subtitle Placement ID=%d, x=%d, y=%d\n", reference->picture_id, reference->x, reference->y); if (reference->x > avctx->width || reference->y > avctx->height) { av_log(avctx, AV_LOG_ERROR, "Subtitle out of video bounds. x = %d, y = %d, video width = %d, video height = %d.\n", reference->x, reference->y, avctx->width, avctx->height); reference->x = 0; reference->y = 0; } } } /** * Parse the display segment packet. * * The display segment controls the updating of the display. * * @param avctx contains the current codec context * @param data pointer to the data pertaining the subtitle to display * @param buf pointer to the packet to process * @param buf_size size of packet to process * @todo TODO: Fix start time, relies on correct PTS, currently too late * * @todo TODO: Fix end time, normally cleared by a second display * @todo segment, which is currently ignored as it clears * @todo the subtitle too early. */ static int display_end_segment(AVCodecContext *avctx, void *data, const uint8_t *buf, int buf_size) { AVSubtitle *sub = data; PGSSubContext *ctx = avctx->priv_data; int64_t pts; uint16_t rect; /* * The end display time is a timeout value and is only reached * if the next subtitle is later than timeout or subtitle has * not been cleared by a subsequent empty display command. */ pts = ctx->pts != AV_NOPTS_VALUE ? ctx->pts : sub->pts; memset(sub, 0, sizeof(*sub)); sub->pts = pts; ctx->pts = AV_NOPTS_VALUE; // Blank if last object_count was 0. if (!ctx->presentation.object_count) return 1; sub->start_display_time = 0; sub->end_display_time = 20000; sub->format = 0; sub->num_rects = ctx->presentation.object_count; sub->rects = av_mallocz(sizeof(*sub->rects) * sub->num_rects); for (rect = 0; rect < sub->num_rects; ++rect) { uint16_t picture_id = ctx->presentation.objects[rect].picture_id; sub->rects[rect] = av_mallocz(sizeof(*sub->rects[rect])); sub->rects[rect]->x = ctx->presentation.objects[rect].x; sub->rects[rect]->y = ctx->presentation.objects[rect].y; sub->rects[rect]->w = ctx->pictures[picture_id].w; sub->rects[rect]->h = ctx->pictures[picture_id].h; sub->rects[rect]->type = SUBTITLE_BITMAP; /* Process bitmap */ sub->rects[rect]->pict.linesize[0] = ctx->pictures[picture_id].w; if (ctx->pictures[picture_id].rle) { if (ctx->pictures[picture_id].rle_remaining_len) av_log(avctx, AV_LOG_ERROR, "RLE data length %u is %u bytes shorter than expected\n", ctx->pictures[picture_id].rle_data_len, ctx->pictures[picture_id].rle_remaining_len); if (decode_rle(avctx, sub, rect, ctx->pictures[picture_id].rle, ctx->pictures[picture_id].rle_data_len) < 0) return 0; } /* Allocate memory for colors */ sub->rects[rect]->nb_colors = 256; sub->rects[rect]->pict.data[1] = av_mallocz(AVPALETTE_SIZE); /* Copy the forced flag */ sub->rects[rect]->forced = (ctx->presentation.objects[rect].composition & 0x40) != 0; if (!ctx->forced_subs_only || ctx->presentation.objects[rect].composition & 0x40) memcpy(sub->rects[rect]->pict.data[1], ctx->clut, sub->rects[rect]->nb_colors * sizeof(uint32_t)); } return 1; } static int decode(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt) { PGSSubContext *ctx = avctx->priv_data; const uint8_t *buf = avpkt->data; int buf_size = avpkt->size; AVSubtitle *sub = data; const uint8_t *buf_end; uint8_t segment_type; int segment_length; int i; av_dlog(avctx, "PGS sub packet:\n"); for (i = 0; i < buf_size; i++) { av_dlog(avctx, "%02x ", buf[i]); if (i % 16 == 15) av_dlog(avctx, "\n"); } if (i & 15) av_dlog(avctx, "\n"); *data_size = 0; /* Ensure that we have received at a least a segment code and segment length */ if (buf_size < 3) return -1; buf_end = buf + buf_size; /* Step through buffer to identify segments */ while (buf < buf_end) { segment_type = bytestream_get_byte(&buf); segment_length = bytestream_get_be16(&buf); av_dlog(avctx, "Segment Length %d, Segment Type %x\n", segment_length, segment_type); if (segment_type != DISPLAY_SEGMENT && segment_length > buf_end - buf) break; switch (segment_type) { case PALETTE_SEGMENT: parse_palette_segment(avctx, buf, segment_length); break; case PICTURE_SEGMENT: parse_picture_segment(avctx, buf, segment_length); break; case PRESENTATION_SEGMENT: parse_presentation_segment(avctx, buf, segment_length); ctx->pts = sub->pts; break; case WINDOW_SEGMENT: /* * Window Segment Structure (No new information provided): * 2 bytes: Unknown, * 2 bytes: X position of subtitle, * 2 bytes: Y position of subtitle, * 2 bytes: Width of subtitle, * 2 bytes: Height of subtitle. */ break; case DISPLAY_SEGMENT: *data_size = display_end_segment(avctx, data, buf, segment_length); break; default: av_log(avctx, AV_LOG_ERROR, "Unknown subtitle segment type 0x%x, length %d\n", segment_type, segment_length); break; } buf += segment_length; } return buf_size; } #define OFFSET(x) offsetof(PGSSubContext, x) #define SD AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_DECODING_PARAM static const AVOption options[] = { {"forced_subs_only", "Only show forced subtitles", OFFSET(forced_subs_only), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, SD}, { NULL }, }; static const AVClass pgsdec_class = { .class_name = "PGS subtitle decoder", .item_name = av_default_item_name, .option = options, .version = LIBAVUTIL_VERSION_INT, }; AVCodec ff_pgssub_decoder = { .name = "pgssub", .type = AVMEDIA_TYPE_SUBTITLE, .id = AV_CODEC_ID_HDMV_PGS_SUBTITLE, .priv_data_size = sizeof(PGSSubContext), .init = init_decoder, .close = close_decoder, .decode = decode, .long_name = NULL_IF_CONFIG_SMALL("HDMV Presentation Graphic Stream subtitles"), .priv_class = &pgsdec_class, };