diff options
| -rw-r--r-- | libavcodec/ac3dec.c | 7 | ||||
| -rw-r--r-- | libavcodec/ac3dec.h | 4 | ||||
| -rw-r--r-- | libavcodec/ac3dec_fixed.c | 1 | ||||
| -rw-r--r-- | libavcodec/ac3dec_float.c | 1 |
4 files changed, 13 insertions, 0 deletions
diff --git a/libavcodec/ac3dec.c b/libavcodec/ac3dec.c index 499971acce..44991600ec 100644 --- a/libavcodec/ac3dec.c +++ b/libavcodec/ac3dec.c @@ -1426,6 +1426,13 @@ static int ac3_decode_frame(AVCodecContext * avctx, void *data, (const uint16_t *) buf, cnt); } else memcpy(s->input_buffer, buf, FFMIN(buf_size, AC3_FRAME_BUFFER_SIZE)); + + /* if consistent noise generation is enabled, seed the linear feedback generator + * with the contents of the AC-3 frame so that the noise is identical across + * decodes given the same AC-3 frame data, for use with non-linear edititing software. */ + if (s->consistent_noise_generation) + av_lfg_init_from_data(&s->dith_state, s->input_buffer, FFMIN(buf_size, AC3_FRAME_BUFFER_SIZE)); + buf = s->input_buffer; /* initialize the GetBitContext with the start of valid AC-3 Frame */ if ((ret = init_get_bits8(&s->gbc, buf, buf_size)) < 0) diff --git a/libavcodec/ac3dec.h b/libavcodec/ac3dec.h index 6cd67c0f21..495e9a69a1 100644 --- a/libavcodec/ac3dec.h +++ b/libavcodec/ac3dec.h @@ -177,6 +177,10 @@ typedef struct AC3DecodeContext { int end_freq[AC3_MAX_CHANNELS]; ///< end frequency bin (endmant) ///@} +///@name Consistent noise generation + int consistent_noise_generation; ///< seed noise generation with AC-3 frame on decode +///@} + ///@name Rematrixing int num_rematrixing_bands; ///< number of rematrixing bands (nrematbnd) int rematrixing_flags[4]; ///< rematrixing flags (rematflg) diff --git a/libavcodec/ac3dec_fixed.c b/libavcodec/ac3dec_fixed.c index 6416da436e..1f79adee34 100644 --- a/libavcodec/ac3dec_fixed.c +++ b/libavcodec/ac3dec_fixed.c @@ -168,6 +168,7 @@ static void ac3_downmix_c_fixed16(int16_t **samples, int16_t (*matrix)[2], #include "ac3dec.c" static const AVOption options[] = { + { "cons_noisegen", "enable consistent noise generation", OFFSET(consistent_noise_generation), AV_OPT_TYPE_BOOL, {.i64 = 0 }, 0, 1, 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 }, { "heavy_compr", "enable heavy dynamic range compression", OFFSET(heavy_compression), AV_OPT_TYPE_BOOL, {.i64 = 0 }, 0, 1, PAR }, { NULL}, diff --git a/libavcodec/ac3dec_float.c b/libavcodec/ac3dec_float.c index 0a5319a303..b85a4ce336 100644 --- a/libavcodec/ac3dec_float.c +++ b/libavcodec/ac3dec_float.c @@ -32,6 +32,7 @@ #include "ac3dec.c" static const AVOption options[] = { + { "cons_noisegen", "enable consistent noise generation", OFFSET(consistent_noise_generation), AV_OPT_TYPE_BOOL, {.i64 = 0 }, 0, 1, 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 }, { "heavy_compr", "enable heavy dynamic range compression", OFFSET(heavy_compression), AV_OPT_TYPE_BOOL, {.i64 = 0 }, 0, 1, PAR }, { "target_level", "target level in -dBFS (0 not applied)", OFFSET(target_level), AV_OPT_TYPE_INT, {.i64 = 0 }, -31, 0, PAR }, |