adding ffmpeg specific version

1 files changed, 739 insertions, 0 deletions

diff --git a/ffmpeg1/libavresample/audio_mix.c b/ffmpeg1/libavresample/audio_mix.c
new file mode 100644
index 0000000..b69bfbc
--- /dev/null
+++ b/ffmpeg1/libavresample/audio_mix.c
@@ -0,0 +1,739 @@
+/*
+ * 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
+ */
+
+#include <stdint.h>
+
+#include "libavutil/common.h"
+#include "libavutil/libm.h"
+#include "libavutil/samplefmt.h"
+#include "avresample.h"
+#include "internal.h"
+#include "audio_data.h"
+#include "audio_mix.h"
+
+static const char *coeff_type_names[] = { "q8", "q15", "flt" };
+
+struct AudioMix {
+    AVAudioResampleContext *avr;
+    enum AVSampleFormat fmt;
+    enum AVMixCoeffType coeff_type;
+    uint64_t in_layout;
+    uint64_t out_layout;
+    int in_channels;
+    int out_channels;
+
+    int ptr_align;
+    int samples_align;
+    int has_optimized_func;
+    const char *func_descr;
+    const char *func_descr_generic;
+    mix_func *mix;
+    mix_func *mix_generic;
+
+    int in_matrix_channels;
+    int out_matrix_channels;
+    int output_zero[AVRESAMPLE_MAX_CHANNELS];
+    int input_skip[AVRESAMPLE_MAX_CHANNELS];
+    int output_skip[AVRESAMPLE_MAX_CHANNELS];
+    int16_t *matrix_q8[AVRESAMPLE_MAX_CHANNELS];
+    int32_t *matrix_q15[AVRESAMPLE_MAX_CHANNELS];
+    float   *matrix_flt[AVRESAMPLE_MAX_CHANNELS];
+    void   **matrix;
+};
+
+void ff_audio_mix_set_func(AudioMix *am, enum AVSampleFormat fmt,
+                           enum AVMixCoeffType coeff_type, int in_channels,
+                           int out_channels, int ptr_align, int samples_align,
+                           const char *descr, void *mix_func)
+{
+    if (fmt == am->fmt && coeff_type == am->coeff_type &&
+        ( in_channels ==  am->in_matrix_channels ||  in_channels == 0) &&
+        (out_channels == am->out_matrix_channels || out_channels == 0)) {
+        char chan_str[16];
+        am->mix           = mix_func;
+        am->func_descr    = descr;
+        am->ptr_align     = ptr_align;
+        am->samples_align = samples_align;
+        if (ptr_align == 1 && samples_align == 1) {
+            am->mix_generic        = mix_func;
+            am->func_descr_generic = descr;
+        } else {
+            am->has_optimized_func = 1;
+        }
+        if (in_channels) {
+            if (out_channels)
+                snprintf(chan_str, sizeof(chan_str), "[%d to %d] ",
+                         in_channels, out_channels);
+            else
+                snprintf(chan_str, sizeof(chan_str), "[%d to any] ",
+                         in_channels);
+        } else if (out_channels) {
+                snprintf(chan_str, sizeof(chan_str), "[any to %d] ",
+                         out_channels);
+        } else {
+            snprintf(chan_str, sizeof(chan_str), "[any to any] ");
+        }
+        av_log(am->avr, AV_LOG_DEBUG, "audio_mix: found function: [fmt=%s] "
+               "[c=%s] %s(%s)\n", av_get_sample_fmt_name(fmt),
+               coeff_type_names[coeff_type], chan_str, descr);
+    }
+}
+
+#define MIX_FUNC_NAME(fmt, cfmt) mix_any_ ## fmt ##_## cfmt ##_c
+
+#define MIX_FUNC_GENERIC(fmt, cfmt, stype, ctype, sumtype, expr)            \
+static void MIX_FUNC_NAME(fmt, cfmt)(stype **samples, ctype **matrix,       \
+                                     int len, int out_ch, int in_ch)        \
+{                                                                           \
+    int i, in, out;                                                         \
+    stype temp[AVRESAMPLE_MAX_CHANNELS];                                    \
+    for (i = 0; i < len; i++) {                                             \
+        for (out = 0; out < out_ch; out++) {                                \
+            sumtype sum = 0;                                                \
+            for (in = 0; in < in_ch; in++)                                  \
+                sum += samples[in][i] * matrix[out][in];                    \
+            temp[out] = expr;                                               \
+        }                                                                   \
+        for (out = 0; out < out_ch; out++)                                  \
+            samples[out][i] = temp[out];                                    \
+    }                                                                       \
+}
+
+MIX_FUNC_GENERIC(FLTP, FLT, float,   float,   float,   sum)
+MIX_FUNC_GENERIC(S16P, FLT, int16_t, float,   float,   av_clip_int16(lrintf(sum)))
+MIX_FUNC_GENERIC(S16P, Q15, int16_t, int32_t, int64_t, av_clip_int16(sum >> 15))
+MIX_FUNC_GENERIC(S16P, Q8,  int16_t, int16_t, int32_t, av_clip_int16(sum >>  8))
+
+/* TODO: templatize the channel-specific C functions */
+
+static void mix_2_to_1_fltp_flt_c(float **samples, float **matrix, int len,
+                                  int out_ch, int in_ch)
+{
+    float *src0 = samples[0];
+    float *src1 = samples[1];
+    float *dst  = src0;
+    float m0    = matrix[0][0];
+    float m1    = matrix[0][1];
+
+    while (len > 4) {
+        *dst++ = *src0++ * m0 + *src1++ * m1;
+        *dst++ = *src0++ * m0 + *src1++ * m1;
+        *dst++ = *src0++ * m0 + *src1++ * m1;
+        *dst++ = *src0++ * m0 + *src1++ * m1;
+        len -= 4;
+    }
+    while (len > 0) {
+        *dst++ = *src0++ * m0 + *src1++ * m1;
+        len--;
+    }
+}
+
+static void mix_2_to_1_s16p_flt_c(int16_t **samples, float **matrix, int len,
+                                  int out_ch, int in_ch)
+{
+    int16_t *src0 = samples[0];
+    int16_t *src1 = samples[1];
+    int16_t *dst  = src0;
+    float m0      = matrix[0][0];
+    float m1      = matrix[0][1];
+
+    while (len > 4) {
+        *dst++ = av_clip_int16(lrintf(*src0++ * m0 + *src1++ * m1));
+        *dst++ = av_clip_int16(lrintf(*src0++ * m0 + *src1++ * m1));
+        *dst++ = av_clip_int16(lrintf(*src0++ * m0 + *src1++ * m1));
+        *dst++ = av_clip_int16(lrintf(*src0++ * m0 + *src1++ * m1));
+        len -= 4;
+    }
+    while (len > 0) {
+        *dst++ = av_clip_int16(lrintf(*src0++ * m0 + *src1++ * m1));
+        len--;
+    }
+}
+
+static void mix_2_to_1_s16p_q8_c(int16_t **samples, int16_t **matrix, int len,
+                                 int out_ch, int in_ch)
+{
+    int16_t *src0 = samples[0];
+    int16_t *src1 = samples[1];
+    int16_t *dst  = src0;
+    int16_t m0    = matrix[0][0];
+    int16_t m1    = matrix[0][1];
+
+    while (len > 4) {
+        *dst++ = (*src0++ * m0 + *src1++ * m1) >> 8;
+        *dst++ = (*src0++ * m0 + *src1++ * m1) >> 8;
+        *dst++ = (*src0++ * m0 + *src1++ * m1) >> 8;
+        *dst++ = (*src0++ * m0 + *src1++ * m1) >> 8;
+        len -= 4;
+    }
+    while (len > 0) {
+        *dst++ = (*src0++ * m0 + *src1++ * m1) >> 8;
+        len--;
+    }
+}
+
+static void mix_1_to_2_fltp_flt_c(float **samples, float **matrix, int len,
+                                  int out_ch, int in_ch)
+{
+    float v;
+    float *dst0 = samples[0];
+    float *dst1 = samples[1];
+    float *src  = dst0;
+    float m0    = matrix[0][0];
+    float m1    = matrix[1][0];
+
+    while (len > 4) {
+        v = *src++;
+        *dst0++ = v * m1;
+        *dst1++ = v * m0;
+        v = *src++;
+        *dst0++ = v * m1;
+        *dst1++ = v * m0;
+        v = *src++;
+        *dst0++ = v * m1;
+        *dst1++ = v * m0;
+        v = *src++;
+        *dst0++ = v * m1;
+        *dst1++ = v * m0;
+        len -= 4;
+    }
+    while (len > 0) {
+        v = *src++;
+        *dst0++ = v * m1;
+        *dst1++ = v * m0;
+        len--;
+    }
+}
+
+static void mix_6_to_2_fltp_flt_c(float **samples, float **matrix, int len,
+                                  int out_ch, int in_ch)
+{
+    float v0, v1;
+    float *src0 = samples[0];
+    float *src1 = samples[1];
+    float *src2 = samples[2];
+    float *src3 = samples[3];
+    float *src4 = samples[4];
+    float *src5 = samples[5];
+    float *dst0 = src0;
+    float *dst1 = src1;
+    float *m0   = matrix[0];
+    float *m1   = matrix[1];
+
+    while (len > 0) {
+        v0 = *src0++;
+        v1 = *src1++;
+        *dst0++ = v0      * m0[0] +
+                  v1      * m0[1] +
+                  *src2   * m0[2] +
+                  *src3   * m0[3] +
+                  *src4   * m0[4] +
+                  *src5   * m0[5];
+        *dst1++ = v0      * m1[0] +
+                  v1      * m1[1] +
+                  *src2++ * m1[2] +
+                  *src3++ * m1[3] +
+                  *src4++ * m1[4] +
+                  *src5++ * m1[5];
+        len--;
+    }
+}
+
+static void mix_2_to_6_fltp_flt_c(float **samples, float **matrix, int len,
+                                  int out_ch, int in_ch)
+{
+    float v0, v1;
+    float *dst0 = samples[0];
+    float *dst1 = samples[1];
+    float *dst2 = samples[2];
+    float *dst3 = samples[3];
+    float *dst4 = samples[4];
+    float *dst5 = samples[5];
+    float *src0 = dst0;
+    float *src1 = dst1;
+
+    while (len > 0) {
+        v0 = *src0++;
+        v1 = *src1++;
+        *dst0++ = v0 * matrix[0][0] + v1 * matrix[0][1];
+        *dst1++ = v0 * matrix[1][0] + v1 * matrix[1][1];
+        *dst2++ = v0 * matrix[2][0] + v1 * matrix[2][1];
+        *dst3++ = v0 * matrix[3][0] + v1 * matrix[3][1];
+        *dst4++ = v0 * matrix[4][0] + v1 * matrix[4][1];
+        *dst5++ = v0 * matrix[5][0] + v1 * matrix[5][1];
+        len--;
+    }
+}
+
+static int mix_function_init(AudioMix *am)
+{
+    am->func_descr = am->func_descr_generic = "n/a";
+    am->mix = am->mix_generic = NULL;
+
+    /* no need to set a mix function when we're skipping mixing */
+    if (!am->in_matrix_channels || !am->out_matrix_channels)
+        return 0;
+
+    /* any-to-any C versions */
+
+    ff_audio_mix_set_func(am, AV_SAMPLE_FMT_FLTP, AV_MIX_COEFF_TYPE_FLT,
+                          0, 0, 1, 1, "C", MIX_FUNC_NAME(FLTP, FLT));
+
+    ff_audio_mix_set_func(am, AV_SAMPLE_FMT_S16P, AV_MIX_COEFF_TYPE_FLT,
+                          0, 0, 1, 1, "C", MIX_FUNC_NAME(S16P, FLT));
+
+    ff_audio_mix_set_func(am, AV_SAMPLE_FMT_S16P, AV_MIX_COEFF_TYPE_Q15,
+                          0, 0, 1, 1, "C", MIX_FUNC_NAME(S16P, Q15));
+
+    ff_audio_mix_set_func(am, AV_SAMPLE_FMT_S16P, AV_MIX_COEFF_TYPE_Q8,
+                          0, 0, 1, 1, "C", MIX_FUNC_NAME(S16P, Q8));
+
+    /* channel-specific C versions */
+
+    ff_audio_mix_set_func(am, AV_SAMPLE_FMT_FLTP, AV_MIX_COEFF_TYPE_FLT,
+                          2, 1, 1, 1, "C", mix_2_to_1_fltp_flt_c);
+
+    ff_audio_mix_set_func(am, AV_SAMPLE_FMT_S16P, AV_MIX_COEFF_TYPE_FLT,
+                          2, 1, 1, 1, "C", mix_2_to_1_s16p_flt_c);
+
+    ff_audio_mix_set_func(am, AV_SAMPLE_FMT_S16P, AV_MIX_COEFF_TYPE_Q8,
+                          2, 1, 1, 1, "C", mix_2_to_1_s16p_q8_c);
+
+    ff_audio_mix_set_func(am, AV_SAMPLE_FMT_FLTP, AV_MIX_COEFF_TYPE_FLT,
+                          1, 2, 1, 1, "C", mix_1_to_2_fltp_flt_c);
+
+    ff_audio_mix_set_func(am, AV_SAMPLE_FMT_FLTP, AV_MIX_COEFF_TYPE_FLT,
+                          6, 2, 1, 1, "C", mix_6_to_2_fltp_flt_c);
+
+    ff_audio_mix_set_func(am, AV_SAMPLE_FMT_FLTP, AV_MIX_COEFF_TYPE_FLT,
+                          2, 6, 1, 1, "C", mix_2_to_6_fltp_flt_c);
+
+    if (ARCH_X86)
+        ff_audio_mix_init_x86(am);
+
+    if (!am->mix) {
+        av_log(am->avr, AV_LOG_ERROR, "audio_mix: NO FUNCTION FOUND: [fmt=%s] "
+               "[c=%s] [%d to %d]\n", av_get_sample_fmt_name(am->fmt),
+               coeff_type_names[am->coeff_type], am->in_channels,
+               am->out_channels);
+        return AVERROR_PATCHWELCOME;
+    }
+    return 0;
+}
+
+AudioMix *ff_audio_mix_alloc(AVAudioResampleContext *avr)
+{
+    AudioMix *am;
+    int ret;
+
+    am = av_mallocz(sizeof(*am));
+    if (!am)
+        return NULL;
+    am->avr = avr;
+
+    if (avr->internal_sample_fmt != AV_SAMPLE_FMT_S16P &&
+        avr->internal_sample_fmt != AV_SAMPLE_FMT_FLTP) {
+        av_log(avr, AV_LOG_ERROR, "Unsupported internal format for "
+               "mixing: %s\n",
+               av_get_sample_fmt_name(avr->internal_sample_fmt));
+        goto error;
+    }
+
+    am->fmt          = avr->internal_sample_fmt;
+    am->coeff_type   = avr->mix_coeff_type;
+    am->in_layout    = avr->in_channel_layout;
+    am->out_layout   = avr->out_channel_layout;
+    am->in_channels  = avr->in_channels;
+    am->out_channels = avr->out_channels;
+
+    /* build matrix if the user did not already set one */
+    if (avr->mix_matrix) {
+        ret = ff_audio_mix_set_matrix(am, avr->mix_matrix, avr->in_channels);
+        if (ret < 0)
+            goto error;
+        av_freep(&avr->mix_matrix);
+    } else {
+        double *matrix_dbl = av_mallocz(avr->out_channels * avr->in_channels *
+                                        sizeof(*matrix_dbl));
+        if (!matrix_dbl)
+            goto error;
+
+        ret = avresample_build_matrix(avr->in_channel_layout,
+                                      avr->out_channel_layout,
+                                      avr->center_mix_level,
+                                      avr->surround_mix_level,
+                                      avr->lfe_mix_level,
+                                      avr->normalize_mix_level,
+                                      matrix_dbl,
+                                      avr->in_channels,
+                                      avr->matrix_encoding);
+        if (ret < 0) {
+            av_free(matrix_dbl);
+            goto error;
+        }
+
+        ret = ff_audio_mix_set_matrix(am, matrix_dbl, avr->in_channels);
+        if (ret < 0) {
+            av_log(avr, AV_LOG_ERROR, "error setting mix matrix\n");
+            av_free(matrix_dbl);
+            goto error;
+        }
+
+        av_free(matrix_dbl);
+    }
+
+    return am;
+
+error:
+    av_free(am);
+    return NULL;
+}
+
+void ff_audio_mix_free(AudioMix **am_p)
+{
+    AudioMix *am;
+
+    if (!*am_p)
+        return;
+    am = *am_p;
+
+    if (am->matrix) {
+        av_free(am->matrix[0]);
+        am->matrix = NULL;
+    }
+    memset(am->matrix_q8,  0, sizeof(am->matrix_q8 ));
+    memset(am->matrix_q15, 0, sizeof(am->matrix_q15));
+    memset(am->matrix_flt, 0, sizeof(am->matrix_flt));
+
+    av_freep(am_p);
+}
+
+int ff_audio_mix(AudioMix *am, AudioData *src)
+{
+    int use_generic = 1;
+    int len = src->nb_samples;
+    int i, j;
+
+    /* determine whether to use the optimized function based on pointer and
+       samples alignment in both the input and output */
+    if (am->has_optimized_func) {
+        int aligned_len = FFALIGN(len, am->samples_align);
+        if (!(src->ptr_align % am->ptr_align) &&
+            src->samples_align >= aligned_len) {
+            len = aligned_len;
+            use_generic = 0;
+        }
+    }
+    av_dlog(am->avr, "audio_mix: %d samples - %d to %d channels (%s)\n",
+            src->nb_samples, am->in_channels, am->out_channels,
+            use_generic ? am->func_descr_generic : am->func_descr);
+
+    if (am->in_matrix_channels && am->out_matrix_channels) {
+        uint8_t **data;
+        uint8_t *data0[AVRESAMPLE_MAX_CHANNELS];
+
+        if (am->out_matrix_channels < am->out_channels ||
+             am->in_matrix_channels <  am->in_channels) {
+            for (i = 0, j = 0; i < FFMAX(am->in_channels, am->out_channels); i++) {
+                if (am->input_skip[i] || am->output_skip[i] || am->output_zero[i])
+                    continue;
+                data0[j++] = src->data[i];
+            }
+            data = data0;
+        } else {
+            data = src->data;
+        }
+
+        if (use_generic)
+            am->mix_generic(data, am->matrix, len, am->out_matrix_channels,
+                            am->in_matrix_channels);
+        else
+            am->mix(data, am->matrix, len, am->out_matrix_channels,
+                    am->in_matrix_channels);
+    }
+
+    if (am->out_matrix_channels < am->out_channels) {
+        for (i = 0; i < am->out_channels; i++)
+            if (am->output_zero[i])
+                av_samples_set_silence(&src->data[i], 0, len, 1, am->fmt);
+    }
+
+    ff_audio_data_set_channels(src, am->out_channels);
+
+    return 0;
+}
+
+int ff_audio_mix_get_matrix(AudioMix *am, double *matrix, int stride)
+{
+    int i, o, i0, o0;
+
+    if ( am->in_channels <= 0 ||  am->in_channels > AVRESAMPLE_MAX_CHANNELS ||
+        am->out_channels <= 0 || am->out_channels > AVRESAMPLE_MAX_CHANNELS) {
+        av_log(am->avr, AV_LOG_ERROR, "Invalid channel counts\n");
+        return AVERROR(EINVAL);
+    }
+
+#define GET_MATRIX_CONVERT(suffix, scale)                                   \
+    if (!am->matrix_ ## suffix[0]) {                                        \
+        av_log(am->avr, AV_LOG_ERROR, "matrix is not set\n");               \
+        return AVERROR(EINVAL);                                             \
+    }                                                                       \
+    for (o = 0, o0 = 0; o < am->out_channels; o++) {                        \
+        for (i = 0, i0 = 0; i < am->in_channels; i++) {                     \
+            if (am->input_skip[i] || am->output_zero[o])                    \
+                matrix[o * stride + i] = 0.0;                               \
+            else                                                            \
+                matrix[o * stride + i] = am->matrix_ ## suffix[o0][i0] *    \
+                                         (scale);                           \
+            if (!am->input_skip[i])                                         \
+                i0++;                                                       \
+        }                                                                   \
+        if (!am->output_zero[o])                                            \
+            o0++;                                                           \
+    }
+
+    switch (am->coeff_type) {
+    case AV_MIX_COEFF_TYPE_Q8:
+        GET_MATRIX_CONVERT(q8, 1.0 / 256.0);
+        break;
+    case AV_MIX_COEFF_TYPE_Q15:
+        GET_MATRIX_CONVERT(q15, 1.0 / 32768.0);
+        break;
+    case AV_MIX_COEFF_TYPE_FLT:
+        GET_MATRIX_CONVERT(flt, 1.0);
+        break;
+    default:
+        av_log(am->avr, AV_LOG_ERROR, "Invalid mix coeff type\n");
+        return AVERROR(EINVAL);
+    }
+
+    return 0;
+}
+
+static void reduce_matrix(AudioMix *am, const double *matrix, int stride)
+{
+    int i, o;
+
+    memset(am->output_zero, 0, sizeof(am->output_zero));
+    memset(am->input_skip,  0, sizeof(am->input_skip));
+    memset(am->output_skip, 0, sizeof(am->output_skip));
+
+    /* exclude output channels if they can be zeroed instead of mixed */
+    for (o = 0; o < am->out_channels; o++) {
+        int zero = 1;
+
+        /* check if the output is always silent */
+        for (i = 0; i < am->in_channels; i++) {
+            if (matrix[o * stride + i] != 0.0) {
+                zero = 0;
+                break;
+            }
+        }
+        /* check if the corresponding input channel makes a contribution to
+           any output channel */
+        if (o < am->in_channels) {
+            for (i = 0; i < am->out_channels; i++) {
+                if (matrix[i * stride + o] != 0.0) {
+                    zero = 0;
+                    break;
+                }
+            }
+        }
+        if (zero) {
+            am->output_zero[o] = 1;
+            am->out_matrix_channels--;
+        }
+    }
+    if (am->out_matrix_channels == 0) {
+        am->in_matrix_channels = 0;
+        return;
+    }
+
+    /* skip input channels that contribute fully only to the corresponding
+       output channel */
+    for (i = 0; i < FFMIN(am->in_channels, am->out_channels); i++) {
+        int skip = 1;
+
+        for (o = 0; o < am->out_channels; o++) {
+            int i0;
+            if ((o != i && matrix[o * stride + i] != 0.0) ||
+                (o == i && matrix[o * stride + i] != 1.0)) {
+                skip = 0;
+                break;
+            }
+            /* if the input contributes fully to the output, also check that no
+               other inputs contribute to this output */
+            if (o == i) {
+                for (i0 = 0; i0 < am->in_channels; i0++) {
+                    if (i0 != i && matrix[o * stride + i0] != 0.0) {
+                        skip = 0;
+                        break;
+                    }
+                }
+            }
+        }
+        if (skip) {
+            am->input_skip[i] = 1;
+            am->in_matrix_channels--;
+        }
+    }
+    /* skip input channels that do not contribute to any output channel */
+    for (; i < am->in_channels; i++) {
+        int contrib = 0;
+
+        for (o = 0; o < am->out_channels; o++) {
+            if (matrix[o * stride + i] != 0.0) {
+                contrib = 1;
+                break;
+            }
+        }
+        if (!contrib) {
+            am->input_skip[i] = 1;
+            am->in_matrix_channels--;
+        }
+    }
+    if (am->in_matrix_channels == 0) {
+        am->out_matrix_channels = 0;
+        return;
+    }
+
+    /* skip output channels that only get full contribution from the
+       corresponding input channel */
+    for (o = 0; o < FFMIN(am->in_channels, am->out_channels); o++) {
+        int skip = 1;
+        int o0;
+
+        for (i = 0; i < am->in_channels; i++) {
+            if ((o != i && matrix[o * stride + i] != 0.0) ||
+                (o == i && matrix[o * stride + i] != 1.0)) {
+                skip = 0;
+                break;
+            }
+        }
+        /* check if the corresponding input channel makes a contribution to
+           any other output channel */
+        i = o;
+        for (o0 = 0; o0 < am->out_channels; o0++) {
+            if (o0 != i && matrix[o0 * stride + i] != 0.0) {
+                skip = 0;
+                break;
+            }
+        }
+        if (skip) {
+            am->output_skip[o] = 1;
+            am->out_matrix_channels--;
+        }
+    }
+    if (am->out_matrix_channels == 0) {
+        am->in_matrix_channels = 0;
+        return;
+    }
+}
+
+int ff_audio_mix_set_matrix(AudioMix *am, const double *matrix, int stride)
+{
+    int i, o, i0, o0, ret;
+    char in_layout_name[128];
+    char out_layout_name[128];
+
+    if ( am->in_channels <= 0 ||  am->in_channels > AVRESAMPLE_MAX_CHANNELS ||
+        am->out_channels <= 0 || am->out_channels > AVRESAMPLE_MAX_CHANNELS) {
+        av_log(am->avr, AV_LOG_ERROR, "Invalid channel counts\n");
+        return AVERROR(EINVAL);
+    }
+
+    if (am->matrix) {
+        av_free(am->matrix[0]);
+        am->matrix = NULL;
+    }
+
+    am->in_matrix_channels  = am->in_channels;
+    am->out_matrix_channels = am->out_channels;
+
+    reduce_matrix(am, matrix, stride);
+
+#define CONVERT_MATRIX(type, expr)                                          \
+    am->matrix_## type[0] = av_mallocz(am->out_matrix_channels *            \
+                                       am->in_matrix_channels  *            \
+                                       sizeof(*am->matrix_## type[0]));     \
+    if (!am->matrix_## type[0])                                             \
+        return AVERROR(ENOMEM);                                             \
+    for (o = 0, o0 = 0; o < am->out_channels; o++) {                        \
+        if (am->output_zero[o] || am->output_skip[o])                       \
+            continue;                                                       \
+        if (o0 > 0)                                                         \
+            am->matrix_## type[o0] = am->matrix_## type[o0 - 1] +           \
+                                     am->in_matrix_channels;                \
+        for (i = 0, i0 = 0; i < am->in_channels; i++) {                     \
+            double v;                                                       \
+            if (am->input_skip[i])                                          \
+                continue;                                                   \
+            v = matrix[o * stride + i];                                     \
+            am->matrix_## type[o0][i0] = expr;                              \
+            i0++;                                                           \
+        }                                                                   \
+        o0++;                                                               \
+    }                                                                       \
+    am->matrix = (void **)am->matrix_## type;
+
+    if (am->in_matrix_channels && am->out_matrix_channels) {
+        switch (am->coeff_type) {
+        case AV_MIX_COEFF_TYPE_Q8:
+            CONVERT_MATRIX(q8, av_clip_int16(lrint(256.0 * v)))
+            break;
+        case AV_MIX_COEFF_TYPE_Q15:
+            CONVERT_MATRIX(q15, av_clipl_int32(llrint(32768.0 * v)))
+            break;
+        case AV_MIX_COEFF_TYPE_FLT:
+            CONVERT_MATRIX(flt, v)
+            break;
+        default:
+            av_log(am->avr, AV_LOG_ERROR, "Invalid mix coeff type\n");
+            return AVERROR(EINVAL);
+        }
+    }
+
+    ret = mix_function_init(am);
+    if (ret < 0)
+        return ret;
+
+    av_get_channel_layout_string(in_layout_name, sizeof(in_layout_name),
+                                 am->in_channels, am->in_layout);
+    av_get_channel_layout_string(out_layout_name, sizeof(out_layout_name),
+                                 am->out_channels, am->out_layout);
+    av_log(am->avr, AV_LOG_DEBUG, "audio_mix: %s to %s\n",
+           in_layout_name, out_layout_name);
+    av_log(am->avr, AV_LOG_DEBUG, "matrix size: %d x %d\n",
+           am->in_matrix_channels, am->out_matrix_channels);
+    for (o = 0; o < am->out_channels; o++) {
+        for (i = 0; i < am->in_channels; i++) {
+            if (am->output_zero[o])
+                av_log(am->avr, AV_LOG_DEBUG, "  (ZERO)");
+            else if (am->input_skip[i] || am->output_skip[o])
+                av_log(am->avr, AV_LOG_DEBUG, "  (SKIP)");
+            else
+                av_log(am->avr, AV_LOG_DEBUG, "  %0.3f ",
+                       matrix[o * am->in_channels + i]);
+        }
+        av_log(am->avr, AV_LOG_DEBUG, "\n");
+    }
+
+    return 0;
+}