static int flashsv_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt) { int buf_size = avpkt->size; FlashSVContext *s = avctx->priv_data; int h_blocks, v_blocks, h_part, v_part, i, j; GetBitContext gb; /* no supplementary picture */ if (buf_size == 0) return 0; if (buf_size < 4) return -1; init_get_bits(&gb, avpkt->data, buf_size * 8); /* start to parse the bitstream */ s->block_width = 16 * (get_bits(&gb, 4) + 1); s->image_width = get_bits(&gb, 12); s->block_height = 16 * (get_bits(&gb, 4) + 1); s->image_height = get_bits(&gb, 12); if (s->ver == 2) { skip_bits(&gb, 6); if (get_bits1(&gb)) { av_log_missing_feature(avctx, "iframe", 1); return AVERROR_PATCHWELCOME; } if (get_bits1(&gb)) { av_log_missing_feature(avctx, "Custom palette", 1); return AVERROR_PATCHWELCOME; } } /* calculate number of blocks and size of border (partial) blocks */ h_blocks = s->image_width / s->block_width; h_part = s->image_width % s->block_width; v_blocks = s->image_height / s->block_height; v_part = s->image_height % s->block_height; /* the block size could change between frames, make sure the buffer * is large enough, if not, get a larger one */ if (s->block_size < s->block_width * s->block_height) { int tmpblock_size = 3 * s->block_width * s->block_height; s->tmpblock = av_realloc(s->tmpblock, tmpblock_size); if (!s->tmpblock) { av_log(avctx, AV_LOG_ERROR, "Can't allocate decompression buffer.\n"); return AVERROR(ENOMEM); } if (s->ver == 2) { s->deflate_block_size = calc_deflate_block_size(tmpblock_size); if (s->deflate_block_size <= 0) { av_log(avctx, AV_LOG_ERROR, "Can't determine deflate buffer size.\n"); return -1; } s->deflate_block = av_realloc(s->deflate_block, s->deflate_block_size); if (!s->deflate_block) { av_log(avctx, AV_LOG_ERROR, "Can't allocate deflate buffer.\n"); return AVERROR(ENOMEM); } } } s->block_size = s->block_width * s->block_height; /* initialize the image size once */ if (avctx->width == 0 && avctx->height == 0) { avcodec_set_dimensions(avctx, s->image_width, s->image_height); } /* check for changes of image width and image height */ if (avctx->width != s->image_width || avctx->height != s->image_height) { av_log(avctx, AV_LOG_ERROR, "Frame width or height differs from first frame!\n"); av_log(avctx, AV_LOG_ERROR, "fh = %d, fv %d vs ch = %d, cv = %d\n", avctx->height, avctx->width, s->image_height, s->image_width); return AVERROR_INVALIDDATA; } /* we care for keyframes only in Screen Video v2 */ s->is_keyframe = (avpkt->flags & AV_PKT_FLAG_KEY) && (s->ver == 2); if (s->is_keyframe) { s->keyframedata = av_realloc(s->keyframedata, avpkt->size); memcpy(s->keyframedata, avpkt->data, avpkt->size); } if(s->ver == 2) s->blocks = av_realloc(s->blocks, (v_blocks + !!v_part) * (h_blocks + !!h_part) * sizeof(s->blocks[0])); av_dlog(avctx, "image: %dx%d block: %dx%d num: %dx%d part: %dx%d\n", s->image_width, s->image_height, s->block_width, s->block_height, h_blocks, v_blocks, h_part, v_part); s->frame.reference = 3; s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE; if (avctx->reget_buffer(avctx, &s->frame) < 0) { av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n"); return -1; } /* loop over all block columns */ for (j = 0; j < v_blocks + (v_part ? 1 : 0); j++) { int y_pos = j * s->block_height; // vertical position in frame int cur_blk_height = (j < v_blocks) ? s->block_height : v_part; /* loop over all block rows */ for (i = 0; i < h_blocks + (h_part ? 1 : 0); i++) { int x_pos = i * s->block_width; // horizontal position in frame int cur_blk_width = (i < h_blocks) ? s->block_width : h_part; int has_diff = 0; /* get the size of the compressed zlib chunk */ int size = get_bits(&gb, 16); s->color_depth = 0; s->zlibprime_curr = 0; s->zlibprime_prev = 0; s->diff_start = 0; s->diff_height = cur_blk_height; if (8 * size > get_bits_left(&gb)) { avctx->release_buffer(avctx, &s->frame); s->frame.data[0] = NULL; return AVERROR_INVALIDDATA; } if (s->ver == 2 && size) { skip_bits(&gb, 3); s->color_depth = get_bits(&gb, 2); has_diff = get_bits1(&gb); s->zlibprime_curr = get_bits1(&gb); s->zlibprime_prev = get_bits1(&gb); if (s->color_depth != 0 && s->color_depth != 2) { av_log(avctx, AV_LOG_ERROR, "%dx%d invalid color depth %d\n", i, j, s->color_depth); return AVERROR_INVALIDDATA; } if (has_diff) { if (!s->keyframe) { av_log(avctx, AV_LOG_ERROR, "inter frame without keyframe\n"); return AVERROR_INVALIDDATA; } s->diff_start = get_bits(&gb, 8); s->diff_height = get_bits(&gb, 8); av_log(avctx, AV_LOG_DEBUG, "%dx%d diff start %d height %d\n", i, j, s->diff_start, s->diff_height); size -= 2; } if (s->zlibprime_prev) av_log(avctx, AV_LOG_DEBUG, "%dx%d zlibprime_prev\n", i, j); if (s->zlibprime_curr) { int col = get_bits(&gb, 8); int row = get_bits(&gb, 8); av_log(avctx, AV_LOG_DEBUG, "%dx%d zlibprime_curr %dx%d\n", i, j, col, row); size -= 2; av_log_missing_feature(avctx, "zlibprime_curr", 1); return AVERROR_PATCHWELCOME; } if (!s->blocks && (s->zlibprime_curr || s->zlibprime_prev)) { av_log(avctx, AV_LOG_ERROR, "no data available for zlib " "priming\n"); return AVERROR_INVALIDDATA; } size--; // account for flags byte } if (has_diff) { int k; int off = (s->image_height - y_pos - 1) * s->frame.linesize[0]; for (k = 0; k < cur_blk_height; k++) memcpy(s->frame.data[0] + off - k*s->frame.linesize[0] + x_pos*3, s->keyframe + off - k*s->frame.linesize[0] + x_pos*3, cur_blk_width * 3); } /* skip unchanged blocks, which have size 0 */ if (size) { if (flashsv_decode_block(avctx, avpkt, &gb, size, cur_blk_width, cur_blk_height, x_pos, y_pos, i + j * (h_blocks + !!h_part))) av_log(avctx, AV_LOG_ERROR, "error in decompression of block %dx%d\n", i, j); } } } if (s->is_keyframe && s->ver == 2) { if (!s->keyframe) { s->keyframe = av_malloc(s->frame.linesize[0] * avctx->height); if (!s->keyframe) { av_log(avctx, AV_LOG_ERROR, "Cannot allocate image data\n"); return AVERROR(ENOMEM); } } memcpy(s->keyframe, s->frame.data[0], s->frame.linesize[0] * avctx->height); } *got_frame = 1; *(AVFrame*)data = s->frame; if ((get_bits_count(&gb) / 8) != buf_size) av_log(avctx, AV_LOG_ERROR, "buffer not fully consumed (%d != %d)\n", buf_size, (get_bits_count(&gb) / 8)); /* report that the buffer was completely consumed */ return buf_size; }