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| author | Justin Ruggles <justin.ruggles@gmail.com> | 2012-07-09 10:33:28 -0400 |
|---|---|---|
| committer | Justin Ruggles <justin.ruggles@gmail.com> | 2012-07-19 13:26:45 -0400 |
| commit | d9837434a91dbb3632df335414aad538e5b0a6e9 (patch) | |
| tree | 8ca43b0fc3a068dcb9b1f0289a7b0074999beccc /libavcodec/alac.c | |
| parent | 6e91f62256db72b056f6bc61106809d3994f8e26 (diff) | |
| download | ffmpeg-d9837434a91dbb3632df335414aad538e5b0a6e9.tar.gz | |
alac: limit the rice param before passing to decode_scalar()
reduces the number of parameters to decode_scalar() and slightly simplifies
the code
Diffstat (limited to 'libavcodec/alac.c')
| -rw-r--r-- | libavcodec/alac.c | 16 |
1 files changed, 7 insertions, 9 deletions
diff --git a/libavcodec/alac.c b/libavcodec/alac.c index 8824ae8377..76ef4998d6 100644 --- a/libavcodec/alac.c +++ b/libavcodec/alac.c @@ -77,17 +77,14 @@ typedef struct { int extra_bits; /**< number of extra bits beyond 16-bit */ } ALACContext; -static inline int decode_scalar(GetBitContext *gb, int k, int limit, int readsamplesize){ +static inline int decode_scalar(GetBitContext *gb, int k, int readsamplesize) +{ int x = get_unary_0_9(gb); if (x > 8) { /* RICE THRESHOLD */ /* use alternative encoding */ x = get_bits(gb, readsamplesize); - } else { - if (k >= limit) - k = limit; - - if (k != 1) { + } else if (k != 1) { int extrabits = show_bits(gb, k); /* multiply x by 2^k - 1, as part of their strange algorithm */ @@ -98,7 +95,6 @@ static inline int decode_scalar(GetBitContext *gb, int k, int limit, int readsam skip_bits(gb, k); } else skip_bits(gb, k - 1); - } } return x; } @@ -123,7 +119,8 @@ static void bastardized_rice_decompress(ALACContext *alac, /* read k, that is bits as is */ k = av_log2((history >> 9) + 3); - x = decode_scalar(&alac->gb, k, alac->rice_limit, readsamplesize); + k = FFMIN(k, alac->rice_limit); + x = decode_scalar(&alac->gb, k, readsamplesize); x_modified = sign_modifier + x; final_val = (x_modified + 1) / 2; @@ -148,8 +145,9 @@ static void bastardized_rice_decompress(ALACContext *alac, sign_modifier = 1; k = 7 - av_log2(history) + ((history + 16) >> 6 /* / 64 */); + k = FFMIN(k, alac->rice_limit); - block_size = decode_scalar(&alac->gb, k, alac->rice_limit, 16); + block_size = decode_scalar(&alac->gb, k, 16); if (block_size > 0) { if(block_size >= output_size - output_count){ |