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	lavr: add option for dithering during sample format conversion to s16
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		| @@ -8,6 +8,7 @@ OBJS = audio_convert.o                                                  \ | ||||
|        audio_data.o                                                     \ | ||||
|        audio_mix.o                                                      \ | ||||
|        audio_mix_matrix.o                                               \ | ||||
|        dither.o                                                         \ | ||||
|        options.o                                                        \ | ||||
|        resample.o                                                       \ | ||||
|        utils.o                                                          \ | ||||
|   | ||||
| @@ -29,6 +29,8 @@ | ||||
| #include "libavutil/samplefmt.h" | ||||
| #include "audio_convert.h" | ||||
| #include "audio_data.h" | ||||
| #include "dither.h" | ||||
| #include "internal.h" | ||||
|  | ||||
| enum ConvFuncType { | ||||
|     CONV_FUNC_TYPE_FLAT, | ||||
| @@ -46,6 +48,7 @@ typedef void (conv_func_deinterleave)(uint8_t **out, const uint8_t *in, int len, | ||||
|  | ||||
| struct AudioConvert { | ||||
|     AVAudioResampleContext *avr; | ||||
|     DitherContext *dc; | ||||
|     enum AVSampleFormat in_fmt; | ||||
|     enum AVSampleFormat out_fmt; | ||||
|     int channels; | ||||
| @@ -246,10 +249,18 @@ static void set_generic_function(AudioConvert *ac) | ||||
|     SET_CONV_FUNC_GROUP(AV_SAMPLE_FMT_DBL, AV_SAMPLE_FMT_DBL) | ||||
| } | ||||
|  | ||||
| void ff_audio_convert_free(AudioConvert **ac) | ||||
| { | ||||
|     if (!*ac) | ||||
|         return; | ||||
|     ff_dither_free(&(*ac)->dc); | ||||
|     av_freep(ac); | ||||
| } | ||||
|  | ||||
| AudioConvert *ff_audio_convert_alloc(AVAudioResampleContext *avr, | ||||
|                                      enum AVSampleFormat out_fmt, | ||||
|                                      enum AVSampleFormat in_fmt, | ||||
|                                      int channels) | ||||
|                                      int channels, int sample_rate) | ||||
| { | ||||
|     AudioConvert *ac; | ||||
|     int in_planar, out_planar; | ||||
| @@ -263,6 +274,17 @@ AudioConvert *ff_audio_convert_alloc(AVAudioResampleContext *avr, | ||||
|     ac->in_fmt   = in_fmt; | ||||
|     ac->channels = channels; | ||||
|  | ||||
|     if (avr->dither_method != AV_RESAMPLE_DITHER_NONE          && | ||||
|         av_get_packed_sample_fmt(out_fmt) == AV_SAMPLE_FMT_S16 && | ||||
|         av_get_bytes_per_sample(in_fmt) > 2) { | ||||
|         ac->dc = ff_dither_alloc(avr, out_fmt, in_fmt, channels, sample_rate); | ||||
|         if (!ac->dc) { | ||||
|             av_free(ac); | ||||
|             return NULL; | ||||
|         } | ||||
|         return ac; | ||||
|     } | ||||
|  | ||||
|     in_planar  = av_sample_fmt_is_planar(in_fmt); | ||||
|     out_planar = av_sample_fmt_is_planar(out_fmt); | ||||
|  | ||||
| @@ -289,6 +311,15 @@ int ff_audio_convert(AudioConvert *ac, AudioData *out, AudioData *in) | ||||
|     int use_generic = 1; | ||||
|     int len         = in->nb_samples; | ||||
|  | ||||
|     if (ac->dc) { | ||||
|         /* dithered conversion */ | ||||
|         av_dlog(ac->avr, "%d samples - audio_convert: %s to %s (dithered)\n", | ||||
|                 len, av_get_sample_fmt_name(ac->in_fmt), | ||||
|                 av_get_sample_fmt_name(ac->out_fmt)); | ||||
|  | ||||
|         return ff_convert_dither(ac->dc, out, in); | ||||
|     } | ||||
|  | ||||
|     /* determine whether to use the optimized function based on pointer and | ||||
|        samples alignment in both the input and output */ | ||||
|     if (ac->has_optimized_func) { | ||||
|   | ||||
| @@ -54,16 +54,26 @@ void ff_audio_convert_set_func(AudioConvert *ac, enum AVSampleFormat out_fmt, | ||||
| /** | ||||
|  * Allocate and initialize AudioConvert context for sample format conversion. | ||||
|  * | ||||
|  * @param avr      AVAudioResampleContext | ||||
|  * @param out_fmt  output sample format | ||||
|  * @param in_fmt   input sample format | ||||
|  * @param channels number of channels | ||||
|  * @return         newly-allocated AudioConvert context | ||||
|  * @param avr         AVAudioResampleContext | ||||
|  * @param out_fmt     output sample format | ||||
|  * @param in_fmt      input sample format | ||||
|  * @param channels    number of channels | ||||
|  * @param sample_rate sample rate (used for dithering) | ||||
|  * @return            newly-allocated AudioConvert context | ||||
|  */ | ||||
| AudioConvert *ff_audio_convert_alloc(AVAudioResampleContext *avr, | ||||
|                                      enum AVSampleFormat out_fmt, | ||||
|                                      enum AVSampleFormat in_fmt, | ||||
|                                      int channels); | ||||
|                                      int channels, int sample_rate); | ||||
|  | ||||
| /** | ||||
|  * Free AudioConvert. | ||||
|  * | ||||
|  * The AudioConvert must have been previously allocated with ff_audio_convert_alloc(). | ||||
|  * | ||||
|  * @param ac  AudioConvert struct | ||||
|  */ | ||||
| void ff_audio_convert_free(AudioConvert **ac); | ||||
|  | ||||
| /** | ||||
|  * Convert audio data from one sample format to another. | ||||
|   | ||||
| @@ -119,6 +119,15 @@ enum AVResampleFilterType { | ||||
|     AV_RESAMPLE_FILTER_TYPE_KAISER,             /**< Kaiser Windowed Sinc */ | ||||
| }; | ||||
|  | ||||
| enum AVResampleDitherMethod { | ||||
|     AV_RESAMPLE_DITHER_NONE,            /**< Do not use dithering */ | ||||
|     AV_RESAMPLE_DITHER_RECTANGULAR,     /**< Rectangular Dither */ | ||||
|     AV_RESAMPLE_DITHER_TRIANGULAR,      /**< Triangular Dither*/ | ||||
|     AV_RESAMPLE_DITHER_TRIANGULAR_HP,   /**< Triangular Dither with High Pass */ | ||||
|     AV_RESAMPLE_DITHER_TRIANGULAR_NS,   /**< Triangular Dither with Noise Shaping */ | ||||
|     AV_RESAMPLE_DITHER_NB,              /**< Number of dither types. Not part of ABI. */ | ||||
| }; | ||||
|  | ||||
| /** | ||||
|  * Return the LIBAVRESAMPLE_VERSION_INT constant. | ||||
|  */ | ||||
|   | ||||
							
								
								
									
										423
									
								
								libavresample/dither.c
									
									
									
									
									
										Normal file
									
								
							
							
						
						
									
										423
									
								
								libavresample/dither.c
									
									
									
									
									
										Normal file
									
								
							| @@ -0,0 +1,423 @@ | ||||
| /* | ||||
|  * Copyright (c) 2012 Justin Ruggles <justin.ruggles@gmail.com> | ||||
|  * | ||||
|  * Triangular with Noise Shaping is based on opusfile. | ||||
|  * Copyright (c) 1994-2012 by the Xiph.Org Foundation and contributors | ||||
|  * | ||||
|  * This file is part of Libav. | ||||
|  * | ||||
|  * Libav is free software; you can redistribute it and/or | ||||
|  * modify it under the terms of the GNU Lesser General Public | ||||
|  * License as published by the Free Software Foundation; either | ||||
|  * version 2.1 of the License, or (at your option) any later version. | ||||
|  * | ||||
|  * Libav is distributed in the hope that it will be useful, | ||||
|  * but WITHOUT ANY WARRANTY; without even the implied warranty of | ||||
|  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU | ||||
|  * Lesser General Public License for more details. | ||||
|  * | ||||
|  * You should have received a copy of the GNU Lesser General Public | ||||
|  * License along with Libav; if not, write to the Free Software | ||||
|  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | ||||
|  */ | ||||
|  | ||||
| /** | ||||
|  * @file | ||||
|  * Dithered Audio Sample Quantization | ||||
|  * | ||||
|  * Converts from dbl, flt, or s32 to s16 using dithering. | ||||
|  */ | ||||
|  | ||||
| #include <math.h> | ||||
| #include <stdint.h> | ||||
|  | ||||
| #include "libavutil/common.h" | ||||
| #include "libavutil/lfg.h" | ||||
| #include "libavutil/mem.h" | ||||
| #include "libavutil/samplefmt.h" | ||||
| #include "audio_convert.h" | ||||
| #include "dither.h" | ||||
| #include "internal.h" | ||||
|  | ||||
| typedef struct DitherState { | ||||
|     int mute; | ||||
|     unsigned int seed; | ||||
|     AVLFG lfg; | ||||
|     float *noise_buf; | ||||
|     int noise_buf_size; | ||||
|     int noise_buf_ptr; | ||||
|     float dither_a[4]; | ||||
|     float dither_b[4]; | ||||
| } DitherState; | ||||
|  | ||||
| struct DitherContext { | ||||
|     DitherDSPContext  ddsp; | ||||
|     enum AVResampleDitherMethod method; | ||||
|  | ||||
|     int mute_dither_threshold;  // threshold for disabling dither | ||||
|     int mute_reset_threshold;   // threshold for resetting noise shaping | ||||
|     const float *ns_coef_b;     // noise shaping coeffs | ||||
|     const float *ns_coef_a;     // noise shaping coeffs | ||||
|  | ||||
|     int channels; | ||||
|     DitherState *state;         // dither states for each channel | ||||
|  | ||||
|     AudioData *flt_data;        // input data in fltp | ||||
|     AudioData *s16_data;        // dithered output in s16p | ||||
|     AudioConvert *ac_in;        // converter for input to fltp | ||||
|     AudioConvert *ac_out;       // converter for s16p to s16 (if needed) | ||||
|  | ||||
|     void (*quantize)(int16_t *dst, const float *src, float *dither, int len); | ||||
|     int samples_align; | ||||
| }; | ||||
|  | ||||
| /* mute threshold, in seconds */ | ||||
| #define MUTE_THRESHOLD_SEC 0.000333 | ||||
|  | ||||
| /* scale factor for 16-bit output. | ||||
|    The signal is attenuated slightly to avoid clipping */ | ||||
| #define S16_SCALE 32753.0f | ||||
|  | ||||
| /* scale to convert lfg from INT_MIN/INT_MAX to -0.5/0.5 */ | ||||
| #define LFG_SCALE (1.0f / (2.0f * INT32_MAX)) | ||||
|  | ||||
| /* noise shaping coefficients */ | ||||
|  | ||||
| static const float ns_48_coef_b[4] = { | ||||
|     2.2374f, -0.7339f, -0.1251f, -0.6033f | ||||
| }; | ||||
|  | ||||
| static const float ns_48_coef_a[4] = { | ||||
|     0.9030f, 0.0116f, -0.5853f, -0.2571f | ||||
| }; | ||||
|  | ||||
| static const float ns_44_coef_b[4] = { | ||||
|     2.2061f, -0.4707f, -0.2534f, -0.6213f | ||||
| }; | ||||
|  | ||||
| static const float ns_44_coef_a[4] = { | ||||
|     1.0587f, 0.0676f, -0.6054f, -0.2738f | ||||
| }; | ||||
|  | ||||
| static void dither_int_to_float_rectangular_c(float *dst, int *src, int len) | ||||
| { | ||||
|     int i; | ||||
|     for (i = 0; i < len; i++) | ||||
|         dst[i] = src[i] * LFG_SCALE; | ||||
| } | ||||
|  | ||||
| static void dither_int_to_float_triangular_c(float *dst, int *src0, int len) | ||||
| { | ||||
|     int i; | ||||
|     int *src1  = src0 + len; | ||||
|  | ||||
|     for (i = 0; i < len; i++) { | ||||
|         float r = src0[i] * LFG_SCALE; | ||||
|         r      += src1[i] * LFG_SCALE; | ||||
|         dst[i]  = r; | ||||
|     } | ||||
| } | ||||
|  | ||||
| static void quantize_c(int16_t *dst, const float *src, float *dither, int len) | ||||
| { | ||||
|     int i; | ||||
|     for (i = 0; i < len; i++) | ||||
|         dst[i] = av_clip_int16(lrintf(src[i] * S16_SCALE + dither[i])); | ||||
| } | ||||
|  | ||||
| #define SQRT_1_6 0.40824829046386301723f | ||||
|  | ||||
| static void dither_highpass_filter(float *src, int len) | ||||
| { | ||||
|     int i; | ||||
|  | ||||
|     /* filter is from libswresample in FFmpeg */ | ||||
|     for (i = 0; i < len - 2; i++) | ||||
|         src[i] = (-src[i] + 2 * src[i + 1] - src[i + 2]) * SQRT_1_6; | ||||
| } | ||||
|  | ||||
| static int generate_dither_noise(DitherContext *c, DitherState *state, | ||||
|                                  int min_samples) | ||||
| { | ||||
|     int i; | ||||
|     int nb_samples  = FFALIGN(min_samples, 16) + 16; | ||||
|     int buf_samples = nb_samples * | ||||
|                       (c->method == AV_RESAMPLE_DITHER_RECTANGULAR ? 1 : 2); | ||||
|     unsigned int *noise_buf_ui; | ||||
|  | ||||
|     av_freep(&state->noise_buf); | ||||
|     state->noise_buf_size = state->noise_buf_ptr = 0; | ||||
|  | ||||
|     state->noise_buf = av_malloc(buf_samples * sizeof(*state->noise_buf)); | ||||
|     if (!state->noise_buf) | ||||
|         return AVERROR(ENOMEM); | ||||
|     state->noise_buf_size = FFALIGN(min_samples, 16); | ||||
|     noise_buf_ui          = (unsigned int *)state->noise_buf; | ||||
|  | ||||
|     av_lfg_init(&state->lfg, state->seed); | ||||
|     for (i = 0; i < buf_samples; i++) | ||||
|         noise_buf_ui[i] = av_lfg_get(&state->lfg); | ||||
|  | ||||
|     c->ddsp.dither_int_to_float(state->noise_buf, noise_buf_ui, nb_samples); | ||||
|  | ||||
|     if (c->method == AV_RESAMPLE_DITHER_TRIANGULAR_HP) | ||||
|         dither_highpass_filter(state->noise_buf, nb_samples); | ||||
|  | ||||
|     return 0; | ||||
| } | ||||
|  | ||||
| static void quantize_triangular_ns(DitherContext *c, DitherState *state, | ||||
|                                    int16_t *dst, const float *src, | ||||
|                                    int nb_samples) | ||||
| { | ||||
|     int i, j; | ||||
|     float *dither = &state->noise_buf[state->noise_buf_ptr]; | ||||
|  | ||||
|     if (state->mute > c->mute_reset_threshold) | ||||
|         memset(state->dither_a, 0, sizeof(state->dither_a)); | ||||
|  | ||||
|     for (i = 0; i < nb_samples; i++) { | ||||
|         float err = 0; | ||||
|         float sample = src[i] * S16_SCALE; | ||||
|  | ||||
|         for (j = 0; j < 4; j++) { | ||||
|             err += c->ns_coef_b[j] * state->dither_b[j] - | ||||
|                    c->ns_coef_a[j] * state->dither_a[j]; | ||||
|         } | ||||
|         for (j = 3; j > 0; j--) { | ||||
|             state->dither_a[j] = state->dither_a[j - 1]; | ||||
|             state->dither_b[j] = state->dither_b[j - 1]; | ||||
|         } | ||||
|         state->dither_a[0] = err; | ||||
|         sample -= err; | ||||
|  | ||||
|         if (state->mute > c->mute_dither_threshold) { | ||||
|             dst[i]             = av_clip_int16(lrintf(sample)); | ||||
|             state->dither_b[0] = 0; | ||||
|         } else { | ||||
|             dst[i]             = av_clip_int16(lrintf(sample + dither[i])); | ||||
|             state->dither_b[0] = av_clipf(dst[i] - sample, -1.5f, 1.5f); | ||||
|         } | ||||
|  | ||||
|         state->mute++; | ||||
|         if (src[i]) | ||||
|             state->mute = 0; | ||||
|     } | ||||
| } | ||||
|  | ||||
| static int convert_samples(DitherContext *c, int16_t **dst, float * const *src, | ||||
|                            int channels, int nb_samples) | ||||
| { | ||||
|     int ch, ret; | ||||
|     int aligned_samples = FFALIGN(nb_samples, 16); | ||||
|  | ||||
|     for (ch = 0; ch < channels; ch++) { | ||||
|         DitherState *state = &c->state[ch]; | ||||
|  | ||||
|         if (state->noise_buf_size < aligned_samples) { | ||||
|             ret = generate_dither_noise(c, state, nb_samples); | ||||
|             if (ret < 0) | ||||
|                 return ret; | ||||
|         } else if (state->noise_buf_size - state->noise_buf_ptr < aligned_samples) { | ||||
|             state->noise_buf_ptr = 0; | ||||
|         } | ||||
|  | ||||
|         if (c->method == AV_RESAMPLE_DITHER_TRIANGULAR_NS) { | ||||
|             quantize_triangular_ns(c, state, dst[ch], src[ch], nb_samples); | ||||
|         } else { | ||||
|             c->quantize(dst[ch], src[ch], | ||||
|                         &state->noise_buf[state->noise_buf_ptr], | ||||
|                         FFALIGN(nb_samples, c->samples_align)); | ||||
|         } | ||||
|  | ||||
|         state->noise_buf_ptr += aligned_samples; | ||||
|     } | ||||
|  | ||||
|     return 0; | ||||
| } | ||||
|  | ||||
| int ff_convert_dither(DitherContext *c, AudioData *dst, AudioData *src) | ||||
| { | ||||
|     int ret; | ||||
|     AudioData *flt_data; | ||||
|  | ||||
|     /* output directly to dst if it is planar */ | ||||
|     if (dst->sample_fmt == AV_SAMPLE_FMT_S16P) | ||||
|         c->s16_data = dst; | ||||
|     else { | ||||
|         /* make sure s16_data is large enough for the output */ | ||||
|         ret = ff_audio_data_realloc(c->s16_data, src->nb_samples); | ||||
|         if (ret < 0) | ||||
|             return ret; | ||||
|     } | ||||
|  | ||||
|     if (src->sample_fmt != AV_SAMPLE_FMT_FLTP) { | ||||
|         /* make sure flt_data is large enough for the input */ | ||||
|         ret = ff_audio_data_realloc(c->flt_data, src->nb_samples); | ||||
|         if (ret < 0) | ||||
|             return ret; | ||||
|         flt_data = c->flt_data; | ||||
|  | ||||
|         /* convert input samples to fltp and scale to s16 range */ | ||||
|         ret = ff_audio_convert(c->ac_in, flt_data, src); | ||||
|         if (ret < 0) | ||||
|             return ret; | ||||
|     } else { | ||||
|         flt_data = src; | ||||
|     } | ||||
|  | ||||
|     /* check alignment and padding constraints */ | ||||
|     if (c->method != AV_RESAMPLE_DITHER_TRIANGULAR_NS) { | ||||
|         int ptr_align     = FFMIN(flt_data->ptr_align,     c->s16_data->ptr_align); | ||||
|         int samples_align = FFMIN(flt_data->samples_align, c->s16_data->samples_align); | ||||
|         int aligned_len   = FFALIGN(src->nb_samples, c->ddsp.samples_align); | ||||
|  | ||||
|         if (!(ptr_align % c->ddsp.ptr_align) && samples_align >= aligned_len) { | ||||
|             c->quantize      = c->ddsp.quantize; | ||||
|             c->samples_align = c->ddsp.samples_align; | ||||
|         } else { | ||||
|             c->quantize      = quantize_c; | ||||
|             c->samples_align = 1; | ||||
|         } | ||||
|     } | ||||
|  | ||||
|     ret = convert_samples(c, (int16_t **)c->s16_data->data, | ||||
|                           (float * const *)flt_data->data, src->channels, | ||||
|                           src->nb_samples); | ||||
|     if (ret < 0) | ||||
|         return ret; | ||||
|  | ||||
|     c->s16_data->nb_samples = src->nb_samples; | ||||
|  | ||||
|     /* interleave output to dst if needed */ | ||||
|     if (dst->sample_fmt == AV_SAMPLE_FMT_S16) { | ||||
|         ret = ff_audio_convert(c->ac_out, dst, c->s16_data); | ||||
|         if (ret < 0) | ||||
|             return ret; | ||||
|     } else | ||||
|         c->s16_data = NULL; | ||||
|  | ||||
|     return 0; | ||||
| } | ||||
|  | ||||
| void ff_dither_free(DitherContext **cp) | ||||
| { | ||||
|     DitherContext *c = *cp; | ||||
|     int ch; | ||||
|  | ||||
|     if (!c) | ||||
|         return; | ||||
|     ff_audio_data_free(&c->flt_data); | ||||
|     ff_audio_data_free(&c->s16_data); | ||||
|     ff_audio_convert_free(&c->ac_in); | ||||
|     ff_audio_convert_free(&c->ac_out); | ||||
|     for (ch = 0; ch < c->channels; ch++) | ||||
|         av_free(c->state[ch].noise_buf); | ||||
|     av_free(c->state); | ||||
|     av_freep(cp); | ||||
| } | ||||
|  | ||||
| static void dither_init(DitherDSPContext *ddsp, | ||||
|                         enum AVResampleDitherMethod method) | ||||
| { | ||||
|     ddsp->quantize      = quantize_c; | ||||
|     ddsp->ptr_align     = 1; | ||||
|     ddsp->samples_align = 1; | ||||
|  | ||||
|     if (method == AV_RESAMPLE_DITHER_RECTANGULAR) | ||||
|         ddsp->dither_int_to_float = dither_int_to_float_rectangular_c; | ||||
|     else | ||||
|         ddsp->dither_int_to_float = dither_int_to_float_triangular_c; | ||||
| } | ||||
|  | ||||
| DitherContext *ff_dither_alloc(AVAudioResampleContext *avr, | ||||
|                                enum AVSampleFormat out_fmt, | ||||
|                                enum AVSampleFormat in_fmt, | ||||
|                                int channels, int sample_rate) | ||||
| { | ||||
|     AVLFG seed_gen; | ||||
|     DitherContext *c; | ||||
|     int ch; | ||||
|  | ||||
|     if (av_get_packed_sample_fmt(out_fmt) != AV_SAMPLE_FMT_S16 || | ||||
|         av_get_bytes_per_sample(in_fmt) <= 2) { | ||||
|         av_log(avr, AV_LOG_ERROR, "dithering %s to %s is not supported\n", | ||||
|                av_get_sample_fmt_name(in_fmt), av_get_sample_fmt_name(out_fmt)); | ||||
|         return NULL; | ||||
|     } | ||||
|  | ||||
|     c = av_mallocz(sizeof(*c)); | ||||
|     if (!c) | ||||
|         return NULL; | ||||
|  | ||||
|     if (avr->dither_method == AV_RESAMPLE_DITHER_TRIANGULAR_NS && | ||||
|         sample_rate != 48000 && sample_rate != 44100) { | ||||
|         av_log(avr, AV_LOG_WARNING, "sample rate must be 48000 or 44100 Hz " | ||||
|                "for triangular_ns dither. using triangular_hp instead.\n"); | ||||
|         avr->dither_method = AV_RESAMPLE_DITHER_TRIANGULAR_HP; | ||||
|     } | ||||
|     c->method = avr->dither_method; | ||||
|     dither_init(&c->ddsp, c->method); | ||||
|  | ||||
|     if (c->method == AV_RESAMPLE_DITHER_TRIANGULAR_NS) { | ||||
|         if (sample_rate == 48000) { | ||||
|             c->ns_coef_b = ns_48_coef_b; | ||||
|             c->ns_coef_a = ns_48_coef_a; | ||||
|         } else { | ||||
|             c->ns_coef_b = ns_44_coef_b; | ||||
|             c->ns_coef_a = ns_44_coef_a; | ||||
|         } | ||||
|     } | ||||
|  | ||||
|     /* Either s16 or s16p output format is allowed, but s16p is used | ||||
|        internally, so we need to use a temp buffer and interleave if the output | ||||
|        format is s16 */ | ||||
|     if (out_fmt != AV_SAMPLE_FMT_S16P) { | ||||
|         c->s16_data = ff_audio_data_alloc(channels, 1024, AV_SAMPLE_FMT_S16P, | ||||
|                                           "dither s16 buffer"); | ||||
|         if (!c->s16_data) | ||||
|             goto fail; | ||||
|  | ||||
|         c->ac_out = ff_audio_convert_alloc(avr, out_fmt, AV_SAMPLE_FMT_S16P, | ||||
|                                            channels, sample_rate); | ||||
|         if (!c->ac_out) | ||||
|             goto fail; | ||||
|     } | ||||
|  | ||||
|     if (in_fmt != AV_SAMPLE_FMT_FLTP) { | ||||
|         c->flt_data = ff_audio_data_alloc(channels, 1024, AV_SAMPLE_FMT_FLTP, | ||||
|                                           "dither flt buffer"); | ||||
|         if (!c->flt_data) | ||||
|             goto fail; | ||||
|  | ||||
|         c->ac_in = ff_audio_convert_alloc(avr, AV_SAMPLE_FMT_FLTP, in_fmt, | ||||
|                                           channels, sample_rate); | ||||
|         if (!c->ac_in) | ||||
|             goto fail; | ||||
|     } | ||||
|  | ||||
|     c->state = av_mallocz(channels * sizeof(*c->state)); | ||||
|     if (!c->state) | ||||
|         goto fail; | ||||
|     c->channels = channels; | ||||
|  | ||||
|     /* calculate thresholds for turning off dithering during periods of | ||||
|        silence to avoid replacing digital silence with quiet dither noise */ | ||||
|     c->mute_dither_threshold = lrintf(sample_rate * MUTE_THRESHOLD_SEC); | ||||
|     c->mute_reset_threshold  = c->mute_dither_threshold * 4; | ||||
|  | ||||
|     /* initialize dither states */ | ||||
|     av_lfg_init(&seed_gen, 0xC0FFEE); | ||||
|     for (ch = 0; ch < channels; ch++) { | ||||
|         DitherState *state = &c->state[ch]; | ||||
|         state->mute = c->mute_reset_threshold + 1; | ||||
|         state->seed = av_lfg_get(&seed_gen); | ||||
|         generate_dither_noise(c, state, FFMAX(32768, sample_rate / 2)); | ||||
|     } | ||||
|  | ||||
|     return c; | ||||
|  | ||||
| fail: | ||||
|     ff_dither_free(&c); | ||||
|     return NULL; | ||||
| } | ||||
							
								
								
									
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								libavresample/dither.h
									
									
									
									
									
										Normal file
									
								
							
							
						
						
									
										88
									
								
								libavresample/dither.h
									
									
									
									
									
										Normal file
									
								
							| @@ -0,0 +1,88 @@ | ||||
| /* | ||||
|  * Copyright (c) 2012 Justin Ruggles <justin.ruggles@gmail.com> | ||||
|  * | ||||
|  * This file is part of Libav. | ||||
|  * | ||||
|  * Libav is free software; you can redistribute it and/or | ||||
|  * modify it under the terms of the GNU Lesser General Public | ||||
|  * License as published by the Free Software Foundation; either | ||||
|  * version 2.1 of the License, or (at your option) any later version. | ||||
|  * | ||||
|  * Libav is distributed in the hope that it will be useful, | ||||
|  * but WITHOUT ANY WARRANTY; without even the implied warranty of | ||||
|  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU | ||||
|  * Lesser General Public License for more details. | ||||
|  * | ||||
|  * You should have received a copy of the GNU Lesser General Public | ||||
|  * License along with Libav; if not, write to the Free Software | ||||
|  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | ||||
|  */ | ||||
|  | ||||
| #ifndef AVRESAMPLE_DITHER_H | ||||
| #define AVRESAMPLE_DITHER_H | ||||
|  | ||||
| #include "avresample.h" | ||||
| #include "audio_data.h" | ||||
|  | ||||
| typedef struct DitherContext DitherContext; | ||||
|  | ||||
| typedef struct DitherDSPContext { | ||||
|     /** | ||||
|      * Convert samples from flt to s16 with added dither noise. | ||||
|      * | ||||
|      * @param dst    destination float array, range -0.5 to 0.5 | ||||
|      * @param src    source int array, range INT_MIN to INT_MAX. | ||||
|      * @param dither float dither noise array | ||||
|      * @param len    number of samples | ||||
|      */ | ||||
|     void (*quantize)(int16_t *dst, const float *src, float *dither, int len); | ||||
|  | ||||
|     int ptr_align;      ///< src and dst constraits for quantize() | ||||
|     int samples_align;  ///< len constraits for quantize() | ||||
|  | ||||
|     /** | ||||
|      * Convert dither noise from int to float with triangular distribution. | ||||
|      * | ||||
|      * @param dst  destination float array, range -0.5 to 0.5 | ||||
|      *             constraints: 32-byte aligned | ||||
|      * @param src0 source int array, range INT_MIN to INT_MAX. | ||||
|      *             the array size is len * 2 | ||||
|      *             constraints: 32-byte aligned | ||||
|      * @param len  number of output noise samples | ||||
|      *             constraints: multiple of 16 | ||||
|      */ | ||||
|     void (*dither_int_to_float)(float *dst, int *src0, int len); | ||||
| } DitherDSPContext; | ||||
|  | ||||
| /** | ||||
|  * Allocate and initialize a DitherContext. | ||||
|  * | ||||
|  * The parameters in the AVAudioResampleContext are used to initialize the | ||||
|  * DitherContext. | ||||
|  * | ||||
|  * @param avr  AVAudioResampleContext | ||||
|  * @return     newly-allocated DitherContext | ||||
|  */ | ||||
| DitherContext *ff_dither_alloc(AVAudioResampleContext *avr, | ||||
|                                enum AVSampleFormat out_fmt, | ||||
|                                enum AVSampleFormat in_fmt, | ||||
|                                int channels, int sample_rate); | ||||
|  | ||||
| /** | ||||
|  * Free a DitherContext. | ||||
|  * | ||||
|  * @param c  DitherContext | ||||
|  */ | ||||
| void ff_dither_free(DitherContext **c); | ||||
|  | ||||
| /** | ||||
|  * Convert audio sample format with dithering. | ||||
|  * | ||||
|  * @param c    DitherContext | ||||
|  * @param dst  destination audio data | ||||
|  * @param src  source audio data | ||||
|  * @return     0 if ok, negative AVERROR code on failure | ||||
|  */ | ||||
| int ff_convert_dither(DitherContext *c, AudioData *dst, AudioData *src); | ||||
|  | ||||
| #endif /* AVRESAMPLE_DITHER_H */ | ||||
| @@ -53,6 +53,7 @@ struct AVAudioResampleContext { | ||||
|     double cutoff;                              /**< resampling cutoff frequency. 1.0 corresponds to half the output sample rate */ | ||||
|     enum AVResampleFilterType filter_type;      /**< resampling filter type */ | ||||
|     int kaiser_beta;                            /**< beta value for Kaiser window (only applicable if filter_type == AV_FILTER_TYPE_KAISER) */ | ||||
|     enum AVResampleDitherMethod dither_method;  /**< dither method          */ | ||||
|  | ||||
|     int in_channels;        /**< number of input channels                   */ | ||||
|     int out_channels;       /**< number of output channels                  */ | ||||
|   | ||||
| @@ -63,6 +63,12 @@ static const AVOption options[] = { | ||||
|         { "blackman_nuttall", "Blackman Nuttall Windowed Sinc", 0, AV_OPT_TYPE_CONST, { .i64 = AV_RESAMPLE_FILTER_TYPE_BLACKMAN_NUTTALL }, INT_MIN, INT_MAX, PARAM, "filter_type" }, | ||||
|         { "kaiser",           "Kaiser Windowed Sinc",           0, AV_OPT_TYPE_CONST, { .i64 = AV_RESAMPLE_FILTER_TYPE_KAISER           }, INT_MIN, INT_MAX, PARAM, "filter_type" }, | ||||
|     { "kaiser_beta",            "Kaiser Window Beta",       OFFSET(kaiser_beta),            AV_OPT_TYPE_INT,    { .i64 = 9              }, 2,                    16,                     PARAM }, | ||||
|     { "dither_method",          "Dither Method",            OFFSET(dither_method),          AV_OPT_TYPE_INT,    { .i64 = AV_RESAMPLE_DITHER_NONE }, 0, AV_RESAMPLE_DITHER_NB-1, PARAM, "dither_method"}, | ||||
|         {"none",          "No Dithering",                         0, AV_OPT_TYPE_CONST, { .i64 = AV_RESAMPLE_DITHER_NONE          }, INT_MIN, INT_MAX, PARAM, "dither_method"}, | ||||
|         {"rectangular",   "Rectangular Dither",                   0, AV_OPT_TYPE_CONST, { .i64 = AV_RESAMPLE_DITHER_RECTANGULAR   }, INT_MIN, INT_MAX, PARAM, "dither_method"}, | ||||
|         {"triangular",    "Triangular Dither",                    0, AV_OPT_TYPE_CONST, { .i64 = AV_RESAMPLE_DITHER_TRIANGULAR    }, INT_MIN, INT_MAX, PARAM, "dither_method"}, | ||||
|         {"triangular_hp", "Triangular Dither With High Pass",     0, AV_OPT_TYPE_CONST, { .i64 = AV_RESAMPLE_DITHER_TRIANGULAR_HP }, INT_MIN, INT_MAX, PARAM, "dither_method"}, | ||||
|         {"triangular_ns", "Triangular Dither With Noise Shaping", 0, AV_OPT_TYPE_CONST, { .i64 = AV_RESAMPLE_DITHER_TRIANGULAR_NS }, INT_MIN, INT_MAX, PARAM, "dither_method"}, | ||||
|     { NULL }, | ||||
| }; | ||||
|  | ||||
|   | ||||
| @@ -142,7 +142,8 @@ int avresample_open(AVAudioResampleContext *avr) | ||||
|     /* setup contexts */ | ||||
|     if (avr->in_convert_needed) { | ||||
|         avr->ac_in = ff_audio_convert_alloc(avr, avr->internal_sample_fmt, | ||||
|                                             avr->in_sample_fmt, avr->in_channels); | ||||
|                                             avr->in_sample_fmt, avr->in_channels, | ||||
|                                             avr->in_sample_rate); | ||||
|         if (!avr->ac_in) { | ||||
|             ret = AVERROR(ENOMEM); | ||||
|             goto error; | ||||
| @@ -155,7 +156,8 @@ int avresample_open(AVAudioResampleContext *avr) | ||||
|         else | ||||
|             src_fmt = avr->in_sample_fmt; | ||||
|         avr->ac_out = ff_audio_convert_alloc(avr, avr->out_sample_fmt, src_fmt, | ||||
|                                              avr->out_channels); | ||||
|                                              avr->out_channels, | ||||
|                                              avr->out_sample_rate); | ||||
|         if (!avr->ac_out) { | ||||
|             ret = AVERROR(ENOMEM); | ||||
|             goto error; | ||||
| @@ -190,8 +192,8 @@ void avresample_close(AVAudioResampleContext *avr) | ||||
|     ff_audio_data_free(&avr->out_buffer); | ||||
|     av_audio_fifo_free(avr->out_fifo); | ||||
|     avr->out_fifo = NULL; | ||||
|     av_freep(&avr->ac_in); | ||||
|     av_freep(&avr->ac_out); | ||||
|     ff_audio_convert_free(&avr->ac_in); | ||||
|     ff_audio_convert_free(&avr->ac_out); | ||||
|     ff_audio_resample_free(&avr->resample); | ||||
|     ff_audio_mix_free(&avr->am); | ||||
|     av_freep(&avr->mix_matrix); | ||||
|   | ||||
| @@ -21,7 +21,7 @@ | ||||
|  | ||||
| #define LIBAVRESAMPLE_VERSION_MAJOR  1 | ||||
| #define LIBAVRESAMPLE_VERSION_MINOR  0 | ||||
| #define LIBAVRESAMPLE_VERSION_MICRO  0 | ||||
| #define LIBAVRESAMPLE_VERSION_MICRO  1 | ||||
|  | ||||
| #define LIBAVRESAMPLE_VERSION_INT  AV_VERSION_INT(LIBAVRESAMPLE_VERSION_MAJOR, \ | ||||
|                                                   LIBAVRESAMPLE_VERSION_MINOR, \ | ||||
|   | ||||
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