avcodec/pcm: Avoid indirection when calling float dsp function

Do this by only keeping the only function pointer from the
AVFloatDSPContext that is needed lateron. This also allows to remove the
decoders' close function.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>

libavcodec/pcm.c

@@ -235,13 +235,15 @@ static int pcm_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
 
 typedef struct PCMDecode {
     short   table[256];
-    AVFloatDSPContext *fdsp;
+    void (*vector_fmul_scalar)(float *dst, const float *src, float mul,
+                               int len);
     float   scale;
 } PCMDecode;
 
 static av_cold int pcm_decode_init(AVCodecContext *avctx)
 {
     PCMDecode *s = avctx->priv_data;
+    AVFloatDSPContext *fdsp;
     int i;
 
     if (avctx->channels <= 0) {
@@ -268,9 +270,11 @@ static av_cold int pcm_decode_init(AVCodecContext *avctx)
             return AVERROR_INVALIDDATA;
 
         s->scale = 1. / (1 << (avctx->bits_per_coded_sample - 1));
-        s->fdsp = avpriv_float_dsp_alloc(0);
-        if (!s->fdsp)
+        fdsp = avpriv_float_dsp_alloc(0);
+        if (!fdsp)
             return AVERROR(ENOMEM);
+        s->vector_fmul_scalar = fdsp->vector_fmul_scalar;
+        av_free(fdsp);
         break;
     default:
         break;
@@ -284,15 +288,6 @@ static av_cold int pcm_decode_init(AVCodecContext *avctx)
     return 0;
 }
 
-static av_cold int pcm_decode_close(AVCodecContext *avctx)
-{
-    PCMDecode *s = avctx->priv_data;
-
-    av_freep(&s->fdsp);
-
-    return 0;
-}
-
 /**
  * Read PCM samples macro
  * @param size   Data size of native machine format
@@ -529,9 +524,9 @@ static int pcm_decode_frame(AVCodecContext *avctx, void *data,
 
     if (avctx->codec_id == AV_CODEC_ID_PCM_F16LE ||
         avctx->codec_id == AV_CODEC_ID_PCM_F24LE) {
-        s->fdsp->vector_fmul_scalar((float *)frame->extended_data[0],
-                                    (const float *)frame->extended_data[0],
-                                    s->scale, FFALIGN(frame->nb_samples * avctx->channels, 4));
+        s->vector_fmul_scalar((float *)frame->extended_data[0],
+                              (const float *)frame->extended_data[0],
+                              s->scale, FFALIGN(frame->nb_samples * avctx->channels, 4));
         emms_c();
     }
 
@@ -570,7 +565,6 @@ AVCodec ff_ ## name_ ## _decoder = {                                        \
     .id             = AV_CODEC_ID_ ## id_,                                  \
     .priv_data_size = sizeof(PCMDecode),                                    \
     .init           = pcm_decode_init,                                      \
-    .close          = pcm_decode_close,                                     \
     .decode         = pcm_decode_frame,                                     \
     .capabilities   = AV_CODEC_CAP_DR1,                                     \
     .sample_fmts    = (const enum AVSampleFormat[]){ sample_fmt_,           \