lavr: temporarily store custom matrix in AVAudioResampleContext

This allows AudioMix to be treated the same way as other conversion contexts
and removes the requirement to allocate it at the same time as the
AVAudioResampleContext.

The current matrix get/set functions are split between the public interface
and AudioMix private functions.

6 files changed, 216 insertions, 158 deletions

diff --git a/libavresample/audio_mix.c b/libavresample/audio_mix.c
index dd2f33d27f..3b39ceeca5 100644
--- a/libavresample/audio_mix.c
+++ b/libavresample/audio_mix.c
@@ -302,27 +302,37 @@ static int mix_function_init(AudioMix *am)
     return 0;
 }
 
-int ff_audio_mix_init(AVAudioResampleContext *avr)
+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));
-        return AVERROR(EINVAL);
+        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->am->matrix) {
-        if (avr->am->coeff_type != avr->mix_coeff_type      ||
-            avr->am->in_layout  != avr->in_channel_layout   ||
-            avr->am->out_layout != avr->out_channel_layout) {
-            av_log(avr, AV_LOG_ERROR,
-                   "Custom matrix does not match current parameters\n");
-            return AVERROR(EINVAL);
-        }
+    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 {
         int i, j;
         char in_layout_name[128];
@@ -330,7 +340,7 @@ int ff_audio_mix_init(AVAudioResampleContext *avr)
         double *matrix_dbl = av_mallocz(avr->out_channels * avr->in_channels *
                                         sizeof(*matrix_dbl));
         if (!matrix_dbl)
-            return AVERROR(ENOMEM);
+            goto error;
 
         ret = avresample_build_matrix(avr->in_channel_layout,
                                       avr->out_channel_layout,
@@ -343,7 +353,7 @@ int ff_audio_mix_init(AVAudioResampleContext *avr)
                                       avr->matrix_encoding);
         if (ret < 0) {
             av_free(matrix_dbl);
-            return ret;
+            goto error;
         }
 
         av_get_channel_layout_string(in_layout_name, sizeof(in_layout_name),
@@ -360,32 +370,33 @@ int ff_audio_mix_init(AVAudioResampleContext *avr)
             av_log(avr, AV_LOG_DEBUG, "\n");
         }
 
-        ret = avresample_set_matrix(avr, matrix_dbl, avr->in_channels);
+        ret = ff_audio_mix_set_matrix(am, matrix_dbl, avr->in_channels);
         if (ret < 0) {
             av_free(matrix_dbl);
-            return ret;
+            goto error;
         }
         av_free(matrix_dbl);
     }
 
-    avr->am->fmt          = avr->internal_sample_fmt;
-    avr->am->coeff_type   = avr->mix_coeff_type;
-    avr->am->in_layout    = avr->in_channel_layout;
-    avr->am->out_layout   = avr->out_channel_layout;
-    avr->am->in_channels  = avr->in_channels;
-    avr->am->out_channels = avr->out_channels;
-
-    ret = mix_function_init(avr->am);
+    ret = mix_function_init(am);
     if (ret < 0)
-        return ret;
+        goto error;
 
-    return 0;
+    return am;
+
+error:
+    av_free(am);
+    return NULL;
 }
 
-void ff_audio_mix_close(AudioMix *am)
+void ff_audio_mix_free(AudioMix **am_p)
 {
-    if (!am)
+    AudioMix *am;
+
+    if (!*am_p)
         return;
+    am = *am_p;
+
     if (am->matrix) {
         av_free(am->matrix[0]);
         am->matrix = NULL;
@@ -393,6 +404,8 @@ void ff_audio_mix_close(AudioMix *am)
     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)
@@ -424,3 +437,92 @@ int ff_audio_mix(AudioMix *am, AudioData *src)
 
     return 0;
 }
+
+int ff_audio_mix_get_matrix(AudioMix *am, double *matrix, int stride)
+{
+    int i, o;
+
+    if ( am->in_channels <= 0 ||  am->in_channels > AVRESAMPLE_MAX_CHANNELS ||
+        am->out_channels <= 0 || am->out_channels > AVRESAMPLE_MAX_CHANNELS) {
+        av_log(am, AV_LOG_ERROR, "Invalid channel counts\n");
+        return AVERROR(EINVAL);
+    }
+
+#define GET_MATRIX_CONVERT(suffix, scale)                                   \
+    if (!am->matrix_ ## suffix[0]) {                                        \
+        av_log(am, AV_LOG_ERROR, "matrix is not set\n");                    \
+        return AVERROR(EINVAL);                                             \
+    }                                                                       \
+    for (o = 0; o < am->out_channels; o++)                                  \
+        for (i = 0; i < am->in_channels; i++)                               \
+            matrix[o * stride + i] = am->matrix_ ## suffix[o][i] * (scale);
+
+    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, AV_LOG_ERROR, "Invalid mix coeff type\n");
+        return AVERROR(EINVAL);
+    }
+
+    return 0;
+}
+
+int ff_audio_mix_set_matrix(AudioMix *am, const double *matrix, int stride)
+{
+    int i, o;
+
+    if ( am->in_channels <= 0 ||  am->in_channels > AVRESAMPLE_MAX_CHANNELS ||
+        am->out_channels <= 0 || am->out_channels > AVRESAMPLE_MAX_CHANNELS) {
+        av_log(am, AV_LOG_ERROR, "Invalid channel counts\n");
+        return AVERROR(EINVAL);
+    }
+
+    if (am->matrix) {
+        av_free(am->matrix[0]);
+        am->matrix = NULL;
+    }
+
+#define CONVERT_MATRIX(type, expr)                                          \
+    am->matrix_## type[0] = av_mallocz(am->out_channels * am->in_channels * \
+                                       sizeof(*am->matrix_## type[0]));     \
+    if (!am->matrix_## type[0])                                             \
+        return AVERROR(ENOMEM);                                             \
+    for (o = 0; o < am->out_channels; o++) {                                \
+        if (o > 0)                                                          \
+            am->matrix_## type[o] = am->matrix_## type[o - 1] +             \
+                                    am->in_channels;                        \
+        for (i = 0; i < am->in_channels; i++) {                             \
+            double v = matrix[o * stride + i];                              \
+            am->matrix_## type[o][i] = expr;                                \
+        }                                                                   \
+    }                                                                       \
+    am->matrix = (void **)am->matrix_## type;
+
+    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, AV_LOG_ERROR, "Invalid mix coeff type\n");
+        return AVERROR(EINVAL);
+    }
+
+    /* TODO: detect situations where we can just swap around pointers
+             instead of doing matrix multiplications with 0.0 and 1.0 */
+
+    return 0;
+}
diff --git a/libavresample/audio_mix.h b/libavresample/audio_mix.h
index 2199fffe0e..22faea7c1b 100644
--- a/libavresample/audio_mix.h
+++ b/libavresample/audio_mix.h
@@ -79,28 +79,36 @@ void ff_audio_mix_set_func(AudioMix *am, enum AVSampleFormat fmt,
                            const char *descr, void *mix_func);
 
 /**
- * Initialize the AudioMix context in the AVAudioResampleContext.
+ * Allocate and initialize an AudioMix context.
  *
  * The parameters in the AVAudioResampleContext are used to initialize the
- * AudioMix context and set the mixing matrix.
+ * AudioMix context.
  *
  * @param avr  AVAudioResampleContext
- * @return     0 on success, negative AVERROR code on failure
+ * @return     newly-allocated AudioMix context.
  */
-int ff_audio_mix_init(AVAudioResampleContext *avr);
+AudioMix *ff_audio_mix_alloc(AVAudioResampleContext *avr);
 
 /**
- * Close an AudioMix context.
- *
- * This clears and frees the mixing matrix arrays.
+ * Free an AudioMix context.
  */
-void ff_audio_mix_close(AudioMix *am);
+void ff_audio_mix_free(AudioMix **am);
 
 /**
  * Apply channel mixing to audio data using the current mixing matrix.
  */
 int ff_audio_mix(AudioMix *am, AudioData *src);
 
+/**
+ * Get the current mixing matrix.
+ */
+int ff_audio_mix_get_matrix(AudioMix *am, double *matrix, int stride);
+
+/**
+ * Set the current mixing matrix.
+ */
+int ff_audio_mix_set_matrix(AudioMix *am, const double *matrix, int stride);
+
 /* arch-specific initialization functions */
 
 void ff_audio_mix_init_x86(AudioMix *am);
diff --git a/libavresample/audio_mix_matrix.c b/libavresample/audio_mix_matrix.c
index 01a93367ef..8da1b487a4 100644
--- a/libavresample/audio_mix_matrix.c
+++ b/libavresample/audio_mix_matrix.c
@@ -287,115 +287,3 @@ int avresample_build_matrix(uint64_t in_layout, uint64_t out_layout,
 
     return 0;
 }
-
-int avresample_get_matrix(AVAudioResampleContext *avr, double *matrix,
-                          int stride)
-{
-    int in_channels, out_channels, i, o;
-
-    in_channels  = av_get_channel_layout_nb_channels(avr->in_channel_layout);
-    out_channels = av_get_channel_layout_nb_channels(avr->out_channel_layout);
-
-    if ( in_channels <= 0 ||  in_channels > AVRESAMPLE_MAX_CHANNELS ||
-        out_channels <= 0 || out_channels > AVRESAMPLE_MAX_CHANNELS) {
-        av_log(avr, AV_LOG_ERROR, "Invalid channel layouts\n");
-        return AVERROR(EINVAL);
-    }
-
-    switch (avr->mix_coeff_type) {
-    case AV_MIX_COEFF_TYPE_Q8:
-        if (!avr->am->matrix_q8[0]) {
-            av_log(avr, AV_LOG_ERROR, "matrix is not set\n");
-            return AVERROR(EINVAL);
-        }
-        for (o = 0; o < out_channels; o++)
-            for (i = 0; i < in_channels; i++)
-                matrix[o * stride + i] = avr->am->matrix_q8[o][i] / 256.0;
-        break;
-    case AV_MIX_COEFF_TYPE_Q15:
-        if (!avr->am->matrix_q15[0]) {
-            av_log(avr, AV_LOG_ERROR, "matrix is not set\n");
-            return AVERROR(EINVAL);
-        }
-        for (o = 0; o < out_channels; o++)
-            for (i = 0; i < in_channels; i++)
-                matrix[o * stride + i] = avr->am->matrix_q15[o][i] / 32768.0;
-        break;
-    case AV_MIX_COEFF_TYPE_FLT:
-        if (!avr->am->matrix_flt[0]) {
-            av_log(avr, AV_LOG_ERROR, "matrix is not set\n");
-            return AVERROR(EINVAL);
-        }
-        for (o = 0; o < out_channels; o++)
-            for (i = 0; i < in_channels; i++)
-                matrix[o * stride + i] = avr->am->matrix_flt[o][i];
-        break;
-    default:
-        av_log(avr, AV_LOG_ERROR, "Invalid mix coeff type\n");
-        return AVERROR(EINVAL);
-    }
-
-    return 0;
-}
-
-int avresample_set_matrix(AVAudioResampleContext *avr, const double *matrix,
-                          int stride)
-{
-    int in_channels, out_channels, i, o;
-
-    in_channels  = av_get_channel_layout_nb_channels(avr->in_channel_layout);
-    out_channels = av_get_channel_layout_nb_channels(avr->out_channel_layout);
-
-    if ( in_channels <= 0 ||  in_channels > AVRESAMPLE_MAX_CHANNELS ||
-        out_channels <= 0 || out_channels > AVRESAMPLE_MAX_CHANNELS) {
-        av_log(avr, AV_LOG_ERROR, "Invalid channel layouts\n");
-        return AVERROR(EINVAL);
-    }
-
-    if (avr->am->matrix) {
-        av_free(avr->am->matrix[0]);
-        avr->am->matrix = NULL;
-    }
-
-#define CONVERT_MATRIX(type, expr)                                          \
-    avr->am->matrix_## type[0] = av_mallocz(out_channels * in_channels *    \
-                                            sizeof(*avr->am->matrix_## type[0])); \
-    if (!avr->am->matrix_## type[0])                                        \
-        return AVERROR(ENOMEM);                                             \
-    for (o = 0; o < out_channels; o++) {                                    \
-        if (o > 0)                                                          \
-            avr->am->matrix_## type[o] = avr->am->matrix_## type[o - 1] +   \
-                                         in_channels;                       \
-        for (i = 0; i < in_channels; i++) {                                 \
-            double v = matrix[o * stride + i];                              \
-            avr->am->matrix_## type[o][i] = expr;                           \
-        }                                                                   \
-    }                                                                       \
-    avr->am->matrix = (void **)avr->am->matrix_## type;
-
-    switch (avr->mix_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(avr, AV_LOG_ERROR, "Invalid mix coeff type\n");
-        return AVERROR(EINVAL);
-    }
-
-    /* TODO: detect situations where we can just swap around pointers
-             instead of doing matrix multiplications with 0.0 and 1.0 */
-
-    /* set AudioMix params */
-    avr->am->in_layout    = avr->in_channel_layout;
-    avr->am->out_layout   = avr->out_channel_layout;
-    avr->am->in_channels  = in_channels;
-    avr->am->out_channels = out_channels;
-
-    return 0;
-}
diff --git a/libavresample/internal.h b/libavresample/internal.h
index 006b6fd14a..3fd33fed6a 100644
--- a/libavresample/internal.h
+++ b/libavresample/internal.h
@@ -74,6 +74,12 @@ struct AVAudioResampleContext {
     ResampleContext *resample;  /**< resampling context                      */
     AudioMix *am;               /**< channel mixing context                  */
     enum AVMatrixEncoding matrix_encoding;      /**< matrixed stereo encoding */
+
+    /**
+     * mix matrix
+     * only used if avresample_set_matrix() is called before avresample_open()
+     */
+    double *mix_matrix;
 };
 
 #endif /* AVRESAMPLE_INTERNAL_H */
diff --git a/libavresample/options.c b/libavresample/options.c
index 8f643700cb..824f5e3bc3 100644
--- a/libavresample/options.c
+++ b/libavresample/options.c
@@ -84,13 +84,6 @@ AVAudioResampleContext *avresample_alloc_context(void)
     avr->av_class = &av_resample_context_class;
     av_opt_set_defaults(avr);
 
-    avr->am = av_mallocz(sizeof(*avr->am));
-    if (!avr->am) {
-        av_free(avr);
-        return NULL;
-    }
-    avr->am->avr = avr;
-
     return avr;
 }
 
diff --git a/libavresample/utils.c b/libavresample/utils.c
index 3fdeeb8cc0..8245e6a345 100644
--- a/libavresample/utils.c
+++ b/libavresample/utils.c
@@ -169,9 +169,11 @@ int avresample_open(AVAudioResampleContext *avr)
         }
     }
     if (avr->mixing_needed) {
-        ret = ff_audio_mix_init(avr);
-        if (ret < 0)
+        avr->am = ff_audio_mix_alloc(avr);
+        if (!avr->am) {
+            ret = AVERROR(ENOMEM);
             goto error;
+        }
     }
 
     return 0;
@@ -191,8 +193,8 @@ void avresample_close(AVAudioResampleContext *avr)
     av_freep(&avr->ac_in);
     av_freep(&avr->ac_out);
     ff_audio_resample_free(&avr->resample);
-    ff_audio_mix_close(avr->am);
-    return;
+    ff_audio_mix_free(&avr->am);
+    av_freep(&avr->mix_matrix);
 }
 
 void avresample_free(AVAudioResampleContext **avr)
@@ -200,7 +202,6 @@ void avresample_free(AVAudioResampleContext **avr)
     if (!*avr)
         return;
     avresample_close(*avr);
-    av_freep(&(*avr)->am);
     av_opt_free(*avr);
     av_freep(avr);
 }
@@ -404,6 +405,66 @@ int attribute_align_arg avresample_convert(AVAudioResampleContext *avr,
                                   current_buffer);
 }
 
+int avresample_get_matrix(AVAudioResampleContext *avr, double *matrix,
+                          int stride)
+{
+    int in_channels, out_channels, i, o;
+
+    if (avr->am)
+        return ff_audio_mix_get_matrix(avr->am, matrix, stride);
+
+    in_channels  = av_get_channel_layout_nb_channels(avr->in_channel_layout);
+    out_channels = av_get_channel_layout_nb_channels(avr->out_channel_layout);
+
+    if ( in_channels <= 0 ||  in_channels > AVRESAMPLE_MAX_CHANNELS ||
+        out_channels <= 0 || out_channels > AVRESAMPLE_MAX_CHANNELS) {
+        av_log(avr, AV_LOG_ERROR, "Invalid channel layouts\n");
+        return AVERROR(EINVAL);
+    }
+
+    if (!avr->mix_matrix) {
+        av_log(avr, AV_LOG_ERROR, "matrix is not set\n");
+        return AVERROR(EINVAL);
+    }
+
+    for (o = 0; o < out_channels; o++)
+        for (i = 0; i < in_channels; i++)
+            matrix[o * stride + i] = avr->mix_matrix[o * in_channels + i];
+
+    return 0;
+}
+
+int avresample_set_matrix(AVAudioResampleContext *avr, const double *matrix,
+                          int stride)
+{
+    int in_channels, out_channels, i, o;
+
+    if (avr->am)
+        return ff_audio_mix_set_matrix(avr->am, matrix, stride);
+
+    in_channels  = av_get_channel_layout_nb_channels(avr->in_channel_layout);
+    out_channels = av_get_channel_layout_nb_channels(avr->out_channel_layout);
+
+    if ( in_channels <= 0 ||  in_channels > AVRESAMPLE_MAX_CHANNELS ||
+        out_channels <= 0 || out_channels > AVRESAMPLE_MAX_CHANNELS) {
+        av_log(avr, AV_LOG_ERROR, "Invalid channel layouts\n");
+        return AVERROR(EINVAL);
+    }
+
+    if (avr->mix_matrix)
+        av_freep(&avr->mix_matrix);
+    avr->mix_matrix = av_malloc(in_channels * out_channels *
+                                sizeof(*avr->mix_matrix));
+    if (!avr->mix_matrix)
+        return AVERROR(ENOMEM);
+
+    for (o = 0; o < out_channels; o++)
+        for (i = 0; i < in_channels; i++)
+            avr->mix_matrix[o * in_channels + i] = matrix[o * stride + i];
+
+    return 0;
+}
+
 int avresample_available(AVAudioResampleContext *avr)
 {
     return av_audio_fifo_size(avr->out_fifo);