Module: libav Branch: master Commit: 46e1af3b0f2c28936dfa88063cc5a35f466f5ac3
Author: Kostya Shishkov <[email protected]> Committer: Luca Barbato <[email protected]> Date: Sat Oct 29 19:35:20 2011 +0200 utvideo: handle empty Huffman trees If the frame is filled with the same colour, encoder may produce no data and the fill value is indicated by zero code length (the rest of symbols will have 0xFF for code length, meaning invalid). So such Huffman trees should be treated specially. Signed-off-by: Luca Barbato <[email protected]> --- libavcodec/utvideo.c | 37 +++++++++++++++++++++++++++++++++---- 1 files changed, 33 insertions(+), 4 deletions(-) diff --git a/libavcodec/utvideo.c b/libavcodec/utvideo.c index 5faaa15..4c3b2a1 100644 --- a/libavcodec/utvideo.c +++ b/libavcodec/utvideo.c @@ -66,7 +66,7 @@ static int huff_cmp(const void *a, const void *b) return (aa->len - bb->len)*256 + aa->sym - bb->sym; } -static int build_huff(const uint8_t *src, VLC *vlc) +static int build_huff(const uint8_t *src, VLC *vlc, int *fsym) { int i; HuffEntry he[256]; @@ -76,13 +76,18 @@ static int build_huff(const uint8_t *src, VLC *vlc) uint8_t syms[256]; uint32_t code; + *fsym = -1; for (i = 0; i < 256; i++) { he[i].sym = i; he[i].len = *src++; } qsort(he, 256, sizeof(*he), huff_cmp); - if (!he[0].len || he[0].len > 32) + if (!he[0].len) { + *fsym = he[0].sym; + return 0; + } + if (he[0].len > 32) return -1; last = 255; @@ -112,13 +117,37 @@ static int decode_plane(UtvideoContext *c, int plane_no, int sstart, send; VLC vlc; GetBitContext gb; - int prev; + int prev, fsym; const int cmask = ~(!plane_no && c->avctx->pix_fmt == PIX_FMT_YUV420P); - if (build_huff(src, &vlc)) { + if (build_huff(src, &vlc, &fsym)) { av_log(c->avctx, AV_LOG_ERROR, "Cannot build Huffman codes\n"); return AVERROR_INVALIDDATA; } + if (fsym >= 0) { // build_huff reported a symbol to fill slices with + send = 0; + for (slice = 0; slice < c->slices; slice++) { + uint8_t *dest; + + sstart = send; + send = (height * (slice + 1) / c->slices) & cmask; + dest = dst + sstart * stride; + + prev = 0x80; + for (j = sstart; j < send; j++) { + for (i = 0; i < width * step; i += step) { + pix = fsym; + if (use_pred) { + prev += pix; + pix = prev; + } + dest[i] = pix; + } + dest += stride; + } + } + return 0; + } src += 256; src_size -= 256; _______________________________________________ libav-commits mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-commits
