From d150a147dac67faeaf6b1f25a523ae330168ee1e Mon Sep 17 00:00:00 2001 From: David Mitchell Date: Thu, 19 Jan 2012 07:31:01 -0800 Subject: Improve support for PGS subtitles. The previous implementation assumed that a new picture would always supersede the previous picture. Similarly, presentation segments were assumed to pertain to the most-recently-read picture. However, each presentation segment may refer to 0 or more pictures by their ID. Picture IDs may repeat, and a repeated picture ID indicates that the old picture for that ID is no longer needed and may be discarded. The new implementation allocates a buffer with one slot for each possible picture ID (the picture ID is a 16-bit field) and properly decodes presentation segments so that all relevant pictures are output upon encountering a display segment. Given that most PGS streams are unlikely to use more than a small fraction of the available picture IDs, it would probably be better to use a more memory-efficient data structure. I'm lazy though, so I leave this to a more motivated individual. I've tested the code with MKV files in VLC (a recent revision from their git repo) and with HandBrake (a version that I hacked up to use ffmpeg's PGS subtitle decoder). Review-by: Hendrik Leppkes Signed-off-by: Michael Niedermayer --- libavcodec/pgssubdec.c | 198 +++++++++++++++++++++++++++++-------------------- 1 file changed, 117 insertions(+), 81 deletions(-) (limited to 'libavcodec/pgssubdec.c') diff --git a/libavcodec/pgssubdec.c b/libavcodec/pgssubdec.c index 5a070e435d..2785d25914 100644 --- a/libavcodec/pgssubdec.c +++ b/libavcodec/pgssubdec.c @@ -40,11 +40,16 @@ enum SegmentType { DISPLAY_SEGMENT = 0x80, }; -typedef struct PGSSubPresentation { +typedef struct PGSSubPictureReference { int x; int y; - int id_number; - int object_number; + int picture_id; +} PGSSubPictureReference; + +typedef struct PGSSubPresentation { + int id_number; + int object_count; + PGSSubPictureReference *objects; } PGSSubPresentation; typedef struct PGSSubPicture { @@ -58,22 +63,29 @@ typedef struct PGSSubPicture { typedef struct PGSSubContext { PGSSubPresentation presentation; uint32_t clut[256]; - PGSSubPicture picture; + PGSSubPicture pictures[UINT16_MAX]; } PGSSubContext; static av_cold int init_decoder(AVCodecContext *avctx) { - avctx->pix_fmt = PIX_FMT_PAL8; + 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->picture.rle); - ctx->picture.rle_buffer_size = 0; + 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; } @@ -88,7 +100,7 @@ static av_cold int close_decoder(AVCodecContext *avctx) * @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, +static int decode_rle(AVCodecContext *avctx, AVSubtitle *sub, int rect, const uint8_t *buf, unsigned int buf_size) { const uint8_t *rle_bitmap_end; @@ -96,15 +108,15 @@ static int decode_rle(AVCodecContext *avctx, AVSubtitle *sub, rle_bitmap_end = buf + buf_size; - sub->rects[0]->pict.data[0] = av_malloc(sub->rects[0]->w * sub->rects[0]->h); + sub->rects[rect]->pict.data[0] = av_malloc(sub->rects[rect]->w * sub->rects[rect]->h); - if (!sub->rects[0]->pict.data[0]) + if (!sub->rects[rect]->pict.data[0]) return -1; pixel_count = 0; line_count = 0; - while (buf < rle_bitmap_end && line_count < sub->rects[0]->h) { + while (buf < rle_bitmap_end && line_count < sub->rects[rect]->h) { uint8_t flags, color; int run; @@ -119,27 +131,27 @@ static int decode_rle(AVCodecContext *avctx, AVSubtitle *sub, color = flags & 0x80 ? bytestream_get_byte(&buf) : 0; } - if (run > 0 && pixel_count + run <= sub->rects[0]->w * sub->rects[0]->h) { - memset(sub->rects[0]->pict.data[0] + pixel_count, color, run); + 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[0]->w > 0) + 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[0]->w, sub->rects[0]->w); + pixel_count % sub->rects[rect]->w, sub->rects[rect]->w); line_count++; } } - if (pixel_count < sub->rects[0]->w * sub->rects[0]->h) { + 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[0]->w * sub->rects[0]->h); + av_dlog(avctx, "Pixel Count = %d, Area = %d\n", pixel_count, sub->rects[rect]->w * sub->rects[rect]->h); return 0; } @@ -162,25 +174,28 @@ static int parse_picture_segment(AVCodecContext *avctx, uint8_t sequence_desc; unsigned int rle_bitmap_len, width, height; + uint16_t picture_id; if (buf_size <= 4) return -1; buf_size -= 4; - /* skip 3 unknown bytes: Object ID (2 bytes), Version Number */ - buf += 3; + 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->picture.rle_remaining_len) + if (buf_size > ctx->pictures[picture_id].rle_remaining_len) return -1; - memcpy(ctx->picture.rle + ctx->picture.rle_data_len, buf, buf_size); - ctx->picture.rle_data_len += buf_size; - ctx->picture.rle_remaining_len -= buf_size; + 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; } @@ -202,17 +217,17 @@ static int parse_picture_segment(AVCodecContext *avctx, return -1; } - ctx->picture.w = width; - ctx->picture.h = height; + ctx->pictures[picture_id].w = width; + ctx->pictures[picture_id].h = height; - av_fast_malloc(&ctx->picture.rle, &ctx->picture.rle_buffer_size, rle_bitmap_len); + av_fast_malloc(&ctx->pictures[picture_id].rle, &ctx->pictures[picture_id].rle_buffer_size, rle_bitmap_len); - if (!ctx->picture.rle) + if (!ctx->pictures[picture_id].rle) return -1; - memcpy(ctx->picture.rle, buf, buf_size); - ctx->picture.rle_data_len = buf_size; - ctx->picture.rle_remaining_len = rle_bitmap_len - buf_size; + 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; } @@ -275,11 +290,11 @@ static void parse_presentation_segment(AVCodecContext *avctx, { PGSSubContext *ctx = avctx->priv_data; - int x, y; - 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) @@ -298,34 +313,48 @@ static void parse_presentation_segment(AVCodecContext *avctx, */ buf += 3; - ctx->presentation.object_number = bytestream_get_byte(&buf); - if (!ctx->presentation.object_number) + ctx->presentation.object_count = bytestream_get_byte(&buf); + if (!ctx->presentation.object_count) return; - /* - * Skip 4 bytes of unknown: - * object_id_ref (2 bytes), - * window_id_ref, - * composition_flag (0x80 - object cropped, 0x40 - object forced) - */ - buf += 4; + /* 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; + } - x = bytestream_get_be16(&buf); - y = bytestream_get_be16(&buf); + 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; + } - /* TODO If cropping, cropping_x, cropping_y, cropping_width, cropping_height (all 2 bytes).*/ + 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); - av_dlog(avctx, "Subtitle Placement x=%d, y=%d\n", x, y); + /* + * Skip 2 bytes of unknown: + * window_id_ref, + * composition_flag (0x80 - object cropped, 0x40 - object forced) + */ + buf += 2; - if (x > avctx->width || 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", - x, y, avctx->width, avctx->height); - x = 0; y = 0; - } + reference->x = bytestream_get_be16(&buf); + reference->y = bytestream_get_be16(&buf); - /* Fill in dimensions */ - ctx->presentation.x = x; - ctx->presentation.y = y; + /* 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; + } + } } /** @@ -349,45 +378,52 @@ static int display_end_segment(AVCodecContext *avctx, void *data, AVSubtitle *sub = data; PGSSubContext *ctx = avctx->priv_data; + uint16_t rect; + /* * The end display time is a timeout value and is only reached - * if the next subtitle is later then timeout or subtitle has + * if the next subtitle is later than timeout or subtitle has * not been cleared by a subsequent empty display command. */ - // Blank if last object_number was 0. - // Note that this may be wrong for more complex subtitles. - if (!ctx->presentation.object_number) + memset(sub, 0, sizeof(*sub)); + + // 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->rects = av_mallocz(sizeof(*sub->rects)); - sub->rects[0] = av_mallocz(sizeof(*sub->rects[0])); - sub->num_rects = 1; - - sub->rects[0]->x = ctx->presentation.x; - sub->rects[0]->y = ctx->presentation.y; - sub->rects[0]->w = ctx->picture.w; - sub->rects[0]->h = ctx->picture.h; - sub->rects[0]->type = SUBTITLE_BITMAP; - - /* Process bitmap */ - sub->rects[0]->pict.linesize[0] = ctx->picture.w; - - if (ctx->picture.rle) { - if (ctx->picture.rle_remaining_len) - av_log(avctx, AV_LOG_ERROR, "RLE data length %u is %u bytes shorter than expected\n", - ctx->picture.rle_data_len, ctx->picture.rle_remaining_len); - if(decode_rle(avctx, sub, ctx->picture.rle, ctx->picture.rle_data_len) < 0) - return 0; - } - /* Allocate memory for colors */ - sub->rects[0]->nb_colors = 256; - sub->rects[0]->pict.data[1] = av_mallocz(AVPALETTE_SIZE); + 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); - memcpy(sub->rects[0]->pict.data[1], ctx->clut, sub->rects[0]->nb_colors * sizeof(uint32_t)); + memcpy(sub->rects[rect]->pict.data[1], ctx->clut, sub->rects[rect]->nb_colors * sizeof(uint32_t)); + } return 1; } -- cgit v1.2.3