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| author | Andreas Rheinhardt <andreas.rheinhardt@gmail.com> | 2020-10-25 00:56:42 +0200 |
|---|---|---|
| committer | Andreas Rheinhardt <andreas.rheinhardt@gmail.com> | 2020-12-08 17:51:44 +0100 |
| commit | 09062eece2e8f188330adab9ddd873341dcf9862 (patch) | |
| tree | 91edf4d57fd48050e8cf397d2aec723b319d7d63 | |
| parent | 4df5144102fb45f74ea46cc9c2a5750a7882dfdd (diff) | |
| download | ffmpeg-09062eece2e8f188330adab9ddd873341dcf9862.tar.gz | |
avcodec/cllc: Improve creating VLCs
One can offload the computation of the codes to
ff_init_vlc_from_lengths(); this also improves performance: The number
of decicycles for one call to read_code_table() decreased from 198343
to 148338 with the sample sample-cllc-rgb.avi from the FATE suite; it
has been looped 100 times and the test repeated ten times to test it
sufficiently often.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
| -rw-r--r-- | libavcodec/cllc.c | 14 |
1 files changed, 3 insertions, 11 deletions
diff --git a/libavcodec/cllc.c b/libavcodec/cllc.c index 8b1bc75faa..837e04f173 100644 --- a/libavcodec/cllc.c +++ b/libavcodec/cllc.c @@ -46,11 +46,9 @@ static int read_code_table(CLLCContext *ctx, GetBitContext *gb, VLC *vlc) { uint8_t symbols[256]; uint8_t bits[256]; - uint16_t codes[256]; - int num_lens, num_codes, num_codes_sum, prefix; + int num_lens, num_codes, num_codes_sum; int i, j, count; - prefix = 0; count = 0; num_codes_sum = 0; @@ -74,19 +72,13 @@ static int read_code_table(CLLCContext *ctx, GetBitContext *gb, VLC *vlc) for (j = 0; j < num_codes; j++) { symbols[count] = get_bits(gb, 8); bits[count] = i + 1; - codes[count] = prefix++; count++; } - if (prefix > (65535 - 256)/2) { - return AVERROR_INVALIDDATA; - } - - prefix <<= 1; } - return ff_init_vlc_sparse(vlc, VLC_BITS, count, bits, 1, 1, - codes, 2, 2, symbols, 1, 1, 0); + return ff_init_vlc_from_lengths(vlc, VLC_BITS, count, bits, 1, + symbols, 1, 1, 0, 0, ctx->avctx); } /* |