lavc: don't reuse audio buffers

Any performance gain from this is negligible and not worth the extra
code.

libavcodec/internal.h

@@ -39,9 +39,6 @@ typedef struct InternalBuffer {
     int width;
     int height;
     enum AVPixelFormat pix_fmt;
-    uint8_t **extended_data;
-    int audio_data_size;
-    int nb_channels;
 } InternalBuffer;
 
 typedef struct AVCodecInternal {
@@ -78,6 +75,12 @@ typedef struct AVCodecInternal {
      * padded with silence. Reject all subsequent frames.
      */
     int last_audio_frame;
+
+    /**
+     * The data for the last allocated audio frame.
+     * Stored here so we can free it.
+     */
+    uint8_t *audio_data;
 } AVCodecInternal;
 
 struct AVCodecDefault {

libavcodec/utils.c

@@ -300,72 +300,29 @@ int avcodec_fill_audio_frame(AVFrame *frame, int nb_channels,
 static int audio_get_buffer(AVCodecContext *avctx, AVFrame *frame)
 {
     AVCodecInternal *avci = avctx->internal;
-    InternalBuffer *buf;
     int buf_size, ret;
 
+    av_freep(&avci->audio_data);
     buf_size = av_samples_get_buffer_size(NULL, avctx->channels,
                                           frame->nb_samples, avctx->sample_fmt,
                                           0);
     if (buf_size < 0)
         return AVERROR(EINVAL);
 
-    /* allocate InternalBuffer if needed */
-    if (!avci->buffer) {
-        avci->buffer = av_mallocz(sizeof(InternalBuffer));
-        if (!avci->buffer)
-            return AVERROR(ENOMEM);
-    }
-    buf = avci->buffer;
-
-    /* if there is a previously-used internal buffer, check its size and
-     * channel count to see if we can reuse it */
-    if (buf->extended_data) {
-        /* if current buffer is too small, free it */
-        if (buf->extended_data[0] && buf_size > buf->audio_data_size) {
-            av_free(buf->extended_data[0]);
-            if (buf->extended_data != buf->data)
-                av_free(buf->extended_data);
-            buf->extended_data = NULL;
-            buf->data[0]       = NULL;
-        }
-        /* if number of channels has changed, reset and/or free extended data
-         * pointers but leave data buffer in buf->data[0] for reuse */
-        if (buf->nb_channels != avctx->channels) {
-            if (buf->extended_data != buf->data)
-                av_free(buf->extended_data);
-            buf->extended_data = NULL;
-        }
-    }
-
-    /* if there is no previous buffer or the previous buffer cannot be used
-     * as-is, allocate a new buffer and/or rearrange the channel pointers */
-    if (!buf->extended_data) {
-        if (!buf->data[0]) {
-            if (!(buf->data[0] = av_mallocz(buf_size)))
-                return AVERROR(ENOMEM);
-            buf->audio_data_size = buf_size;
-        }
-        if ((ret = avcodec_fill_audio_frame(frame, avctx->channels,
-                                            avctx->sample_fmt, buf->data[0],
-                                            buf->audio_data_size, 0)))
-            return ret;
+    frame->data[0] = av_mallocz(buf_size);
+    if (!frame->data[0])
+        return AVERROR(ENOMEM);
 
-        if (frame->extended_data == frame->data)
-            buf->extended_data = buf->data;
-        else
-            buf->extended_data = frame->extended_data;
-        memcpy(buf->data, frame->data, sizeof(frame->data));
-        buf->linesize[0] = frame->linesize[0];
-        buf->nb_channels = avctx->channels;
-    } else {
-        /* copy InternalBuffer info to the AVFrame */
-        frame->extended_data = buf->extended_data;
-        frame->linesize[0]   = buf->linesize[0];
-        memcpy(frame->data, buf->data, sizeof(frame->data));
+    ret = avcodec_fill_audio_frame(frame, avctx->channels, avctx->sample_fmt,
+                                   frame->data[0], buf_size, 0);
+    if (ret < 0) {
+        av_freep(&frame->data[0]);
+        return ret;
     }
 
     frame->type = FF_BUFFER_TYPE_INTERNAL;
 
+    avci->audio_data = frame->data[0];
     if (avctx->debug & FF_DEBUG_BUFFERS)
         av_log(avctx, AV_LOG_DEBUG, "default_get_buffer called on frame %p, "
                                     "internal audio buffer used\n", frame);
@@ -1787,18 +1744,7 @@ static void video_free_buffers(AVCodecContext *s)
 static void audio_free_buffers(AVCodecContext *avctx)
 {
     AVCodecInternal *avci = avctx->internal;
-    InternalBuffer *buf;
-
-    if (!avci->buffer)
-        return;
-    buf = avci->buffer;
-
-    if (buf->extended_data) {
-        av_free(buf->extended_data[0]);
-        if (buf->extended_data != buf->data)
-            av_free(buf->extended_data);
-    }
-    av_freep(&avci->buffer);
+    av_freep(&avci->audio_data);
 }
 
 void avcodec_default_free_buffers(AVCodecContext *avctx)