src_buffer: implement audio buffer copy.

libavfilter/src_buffer.c

@@ -220,6 +220,7 @@ static AVFilterBufferRef *copy_buffer_ref(AVFilterContext *ctx,
 {
     AVFilterLink *outlink = ctx->outputs[0];
     AVFilterBufferRef *buf;
+    int channels, data_size, i;
 
     switch (outlink->type) {
 
@@ -231,6 +232,17 @@ static AVFilterBufferRef *copy_buffer_ref(AVFilterContext *ctx,
                       ref->format, ref->video->w, ref->video->h);
         break;
 
+    case AVMEDIA_TYPE_AUDIO:
+        buf = avfilter_get_audio_buffer(outlink, AV_PERM_WRITE,
+                                        ref->audio->nb_samples);
+        channels = av_get_channel_layout_nb_channels(ref->audio->channel_layout);
+        data_size = av_samples_get_buffer_size(NULL, channels,
+                                               ref->audio->nb_samples,
+                                               ref->format, 1);
+        for (i = 0; i < FF_ARRAY_ELEMS(ref->buf->data) && ref->buf->data[i]; i++)
+            memcpy(buf->buf->data[i], ref->buf->data[i], data_size);
+        break;
+
     default:
         return NULL;
     }