diff options
Diffstat (limited to 'contrib')
| -rw-r--r-- | contrib/ffmpeg/A02-ac3dec-asymmetric-drc.patch | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/contrib/ffmpeg/A02-ac3dec-asymmetric-drc.patch b/contrib/ffmpeg/A02-ac3dec-asymmetric-drc.patch new file mode 100644 index 000000000..b87de1602 --- /dev/null +++ b/contrib/ffmpeg/A02-ac3dec-asymmetric-drc.patch @@ -0,0 +1,44 @@ +From e275318cecee53cf8ce13e4ab41df91c8c7fdcd4 Mon Sep 17 00:00:00 2001 +From: John Stebbins <[email protected]> +Date: Mon, 13 Jan 2014 17:04:30 +0000 +Subject: [PATCH] ac3dec: Allow asymmetric application of DRC when drc_scale > + 1 + +Amplification of quiet sounds is enhanced. +Inspired by gbooker's A52Decoder. +--- + libavcodec/ac3dec.c | 11 ++++++++--- + 1 file changed, 8 insertions(+), 3 deletions(-) + +diff --git a/libavcodec/ac3dec.c b/libavcodec/ac3dec.c +index 87638e7..0416dbc 100644 +--- a/libavcodec/ac3dec.c ++++ b/libavcodec/ac3dec.c +@@ -772,8 +772,13 @@ 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; + } +@@ -1487,7 +1492,7 @@ 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}, + }; + +-- +1.8.3.4 (Apple Git-47) + |