From ebe8b5d947c41449c684f17c6826fe6bc46c0360 Mon Sep 17 00:00:00 2001 From: Tom Butterworth Date: Thu, 23 Jul 2015 00:03:29 +0100 Subject: dds: Fix the slice size computation A bug was introduced in 6b2b26e7af3ede0abfb46eb5725c26d1083f50bc whereby when frame height wasn't divisible by the number of threads, pixels would be omitted from the bottom rows during decode. Signed-off-by: Luca Barbato --- libavcodec/dds.c | 26 +++++++++++++++++--------- 1 file changed, 17 insertions(+), 9 deletions(-) (limited to 'libavcodec/dds.c') diff --git a/libavcodec/dds.c b/libavcodec/dds.c index 625cb3027d..2c3a2f25b8 100644 --- a/libavcodec/dds.c +++ b/libavcodec/dds.c @@ -105,7 +105,7 @@ typedef struct DDSContext { const uint8_t *tex_data; // Compressed texture int tex_ratio; // Compression ratio - int slice_size; // Optimal slice size + int slice_count; // Number of slices for threaded operations /* Pointer to the selected compress or decompress function. */ int (*tex_funct)(uint8_t *dst, ptrdiff_t stride, const uint8_t *block); @@ -421,14 +421,23 @@ static int decompress_texture_thread(AVCodecContext *avctx, void *arg, AVFrame *frame = arg; const uint8_t *d = ctx->tex_data; int w_block = avctx->coded_width / TEXTURE_BLOCK_W; + int h_block = avctx->coded_height / TEXTURE_BLOCK_H; int x, y; int start_slice, end_slice; + int base_blocks_per_slice = h_block / ctx->slice_count; + int remainder_blocks = h_block % ctx->slice_count; - start_slice = slice * ctx->slice_size; - end_slice = FFMIN(start_slice + ctx->slice_size, avctx->coded_height); + /* When the frame height (in blocks) doesn't divide evenly between the + * number of slices, spread the remaining blocks evenly between the first + * operations */ + start_slice = slice * base_blocks_per_slice; + /* Add any extra blocks (one per slice) that have been added before this slice */ + start_slice += FFMIN(slice, remainder_blocks); - start_slice /= TEXTURE_BLOCK_H; - end_slice /= TEXTURE_BLOCK_H; + end_slice = start_slice + base_blocks_per_slice; + /* Add an extra block if there are still remainder blocks to be accounted for */ + if (slice < remainder_blocks) + end_slice++; for (y = start_slice; y < end_slice; y++) { uint8_t *p = frame->data[0] + y * frame->linesize[0] * TEXTURE_BLOCK_H; @@ -633,13 +642,12 @@ static int dds_decode(AVCodecContext *avctx, void *data, return ret; if (ctx->compressed) { - int slices = FFMIN(avctx->thread_count, - avctx->coded_height / TEXTURE_BLOCK_H); - ctx->slice_size = avctx->coded_height / slices; + ctx->slice_count = av_clip(avctx->thread_count, 1, + avctx->coded_height / TEXTURE_BLOCK_H); /* Use the decompress function on the texture, one block per thread. */ ctx->tex_data = gbc->buffer; - avctx->execute2(avctx, decompress_texture_thread, frame, NULL, slices); + avctx->execute2(avctx, decompress_texture_thread, frame, NULL, ctx->slice_count); } else { int linesize = av_image_get_linesize(avctx->pix_fmt, frame->width, 0); -- cgit v1.2.3