From 18bb323da437642616bfefcc1d6bc781ca0658b4 Mon Sep 17 00:00:00 2001 From: Andreas Rheinhardt Date: Thu, 1 Apr 2021 16:47:11 +0200 Subject: [PATCH] avcodec/ac3enc: Simplify AC-3 bit counting When encoding E-AC-3, whether coupling is on or not determines whether an additional frame based coupling exponent strategy element frmcplexpstr (of size five bits) is present in the bitstream. So just add five to the number of bits when counting them instead of adding 5*s->cpl_on (the latter field is currently only 0 or 1, so it doesn't make a difference). Furthermore, move some parts of the bit allocation that doesn't change per-frame to count_frame_bits_fixed() (which is only run once during init). Signed-off-by: Andreas Rheinhardt --- libavcodec/ac3enc.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/libavcodec/ac3enc.c b/libavcodec/ac3enc.c index e27858e1b0c..8d9de8e108c 100644 --- a/libavcodec/ac3enc.c +++ b/libavcodec/ac3enc.c @@ -784,6 +784,10 @@ static void count_frame_bits_fixed(AC3EncodeContext *s) if (s->eac3) frame_bits++; + /* coupling strategy exists: cplstre */ + if (!s->eac3) + frame_bits++; + if (!s->eac3) { /* exponent strategy */ frame_bits += 2 * s->fbw_channels; @@ -796,9 +800,8 @@ static void count_frame_bits_fixed(AC3EncodeContext *s) frame_bits += 2 + 2 + 2 + 2 + 3; } - /* converter snr offset */ - if (s->eac3) - frame_bits++; + /* snroffste for AC-3, convsnroffste for E-AC-3 */ + frame_bits++; if (!s->eac3) { /* delta bit allocation */ @@ -904,7 +907,7 @@ static void count_frame_bits(AC3EncodeContext *s) /* coupling exponent strategy */ if (s->cpl_on) { if (s->use_frame_exp_strategy) { - frame_bits += 5 * s->cpl_on; + frame_bits += 5; } else { for (blk = 0; blk < s->num_blocks; blk++) frame_bits += 2 * s->blocks[blk].cpl_in_use; @@ -926,8 +929,6 @@ static void count_frame_bits(AC3EncodeContext *s) AC3Block *block = &s->blocks[blk]; /* coupling strategy */ - if (!s->eac3) - frame_bits++; if (block->new_cpl_strategy) { if (!s->eac3) frame_bits++; @@ -983,7 +984,6 @@ static void count_frame_bits(AC3EncodeContext *s) /* snr offsets and fast gain codes */ if (!s->eac3) { - frame_bits++; if (block->new_snr_offsets) frame_bits += 6 + (s->channels + block->cpl_in_use) * (4 + 3); } -- 2.39.2