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| author | Christophe Gisquet <christophe.gisquet@gmail.com> | 2014-06-15 12:04:36 +0200 |
|---|---|---|
| committer | Michael Niedermayer <michaelni@gmx.at> | 2014-06-16 00:52:09 +0200 |
| commit | f6577bd9cf3e49d522242771184834d6b0c157fd (patch) | |
| tree | adb52be554906c1df501b4076256a5af03ace1f9 /libavcodec/huffyuvdec.c | |
| parent | 02bffc560f5ee91afa62b6c1a1a7012efc161734 (diff) | |
| download | ffmpeg-f6577bd9cf3e49d522242771184834d6b0c157fd.tar.gz | |
huffyuvdec: use unsafe bitstream reader
The reader reads in chunks of 11 bits at most, and at most 3 times. The unsafe
reader therefore may read 6 chunks instead of 1 in worst case, ie 8 bytes,
which is within the padding tolerance.
The reader ends up being ~10% faster. Cumulative effect of unsafe reading and
code block swapping on 3 sequences is for 1 thread, decoding time goes from
23.3s to 19.0s.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Diffstat (limited to 'libavcodec/huffyuvdec.c')
| -rw-r--r-- | libavcodec/huffyuvdec.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/libavcodec/huffyuvdec.c b/libavcodec/huffyuvdec.c index 6691149089..7bb9b2dea0 100644 --- a/libavcodec/huffyuvdec.c +++ b/libavcodec/huffyuvdec.c @@ -30,6 +30,8 @@ * huffyuv decoder */ +#define UNCHECKED_BITSTREAM_READER 1 + #include "avcodec.h" #include "get_bits.h" #include "huffyuv.h" @@ -613,15 +615,21 @@ static av_cold int decode_init_thread_copy(AVCodecContext *avctx) static void decode_422_bitstream(HYuvContext *s, int count) { - int i; + int i, icount; OPEN_READER(re, &s->gb); count /= 2; - if (count >= (get_bits_left(&s->gb)) / (32 * 4)) { - for (i = 0; i < count && get_bits_left(&s->gb) > 0; i++) { + icount = get_bits_left(&s->gb) / (32 * 4); + if (count >= icount) { + for (i = 0; i < icount; i++) { READ_2PIX(s->temp[0][2 * i ], s->temp[1][i], 1); READ_2PIX(s->temp[0][2 * i + 1], s->temp[2][i], 2); } + for (; i < count && get_bits_left(&s->gb) > 0; i++) { + READ_2PIX(s->temp[0][2 * i ], s->temp[1][i], 1); + if (get_bits_left(&s->gb) <= 0) break; + READ_2PIX(s->temp[0][2 * i + 1], s->temp[2][i], 2); + } for (; i < count; i++) s->temp[0][2 * i ] = s->temp[1][i] = s->temp[0][2 * i + 1] = s->temp[2][i] = 128; @@ -716,7 +724,7 @@ static av_always_inline void decode_bgr_1(HYuvContext *s, int count, int i; OPEN_READER(re, &s->gb); - for (i = 0; i < count; i++) { + for (i = 0; i < count && get_bits_left(&s->gb) > 0; i++) { unsigned int index; int code, n; |