diff options
| author | John Stebbins <stebbins@jetheaddev.com> | 2014-01-13 17:04:30 +0000 |
|---|---|---|
| committer | Tim Walker <tdskywalker@gmail.com> | 2014-01-29 23:26:25 +0100 |
| commit | 23d461fe8714a20ee5e6929f22c61512fdda568e (patch) | |
| tree | 73c0d6e09fd919bbabfab4d940501796eacd0543 /libavcodec/ac3dec.c | |
| parent | d67cfdeb530360748ada6ad0335af99507dd6308 (diff) | |
ac3dec: Allow asymmetric application of DRC when drc_scale > 1
Amplification of quiet sounds is enhanced.
Inspired by gbooker's A52Decoder.
Diffstat (limited to 'libavcodec/ac3dec.c')
| -rw-r--r-- | libavcodec/ac3dec.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/libavcodec/ac3dec.c b/libavcodec/ac3dec.c index 2cceadc878..fcb52e11d0 100644 --- a/libavcodec/ac3dec.c +++ b/libavcodec/ac3dec.c @@ -778,8 +778,13 @@ static int decode_audio_block(AC3DecodeContext *s, int blk) i = !s->channel_mode; do { if (get_bits1(gbc)) { - s->dynamic_range[i] = powf(dynamic_range_tab[get_bits(gbc, 8)], - s->drc_scale); + /* Allow asymmetric application of DRC when drc_scale > 1. + Amplification of quiet sounds is enhanced */ + float range = dynamic_range_tab[get_bits(gbc, 8)]; + if (range > 1.0 || s->drc_scale <= 1.0) + s->dynamic_range[i] = powf(range, s->drc_scale); + else + s->dynamic_range[i] = range; } else if (blk == 0) { s->dynamic_range[i] = 1.0f; } @@ -1493,7 +1498,7 @@ static av_cold int ac3_decode_end(AVCodecContext *avctx) #define OFFSET(x) offsetof(AC3DecodeContext, x) #define PAR (AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_AUDIO_PARAM) static const AVOption options[] = { - { "drc_scale", "percentage of dynamic range compression to apply", OFFSET(drc_scale), AV_OPT_TYPE_FLOAT, {.dbl = 1.0}, 0.0, 1.0, PAR }, + { "drc_scale", "percentage of dynamic range compression to apply", OFFSET(drc_scale), AV_OPT_TYPE_FLOAT, {.dbl = 1.0}, 0.0, 6.0, PAR }, { NULL}, }; |