lavc/avcodec: only allocate decoding packets for decoders

libavcodec/avcodec.c

@@ -155,12 +155,7 @@ int attribute_align_arg avcodec_open2(AVCodecContext *avctx, const AVCodec *code
 
     avci->buffer_frame = av_frame_alloc();
     avci->buffer_pkt = av_packet_alloc();
-    avci->in_pkt = av_packet_alloc();
-    avci->last_pkt_props = av_packet_alloc();
-    avci->pkt_props = av_fifo_alloc2(1, sizeof(*avci->last_pkt_props),
-                                     AV_FIFO_FLAG_AUTO_GROW);
-    if (!avci->buffer_frame || !avci->buffer_pkt          ||
-        !avci->in_pkt || !avci->last_pkt_props || !avci->pkt_props) {
+    if (!avci->buffer_frame || !avci->buffer_pkt) {
         ret = AVERROR(ENOMEM);
         goto free_and_end;
     }

libavcodec/decode.c

@@ -1527,6 +1527,7 @@ int ff_reget_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
 
 int ff_decode_preinit(AVCodecContext *avctx)
 {
+    AVCodecInternal *avci = avctx->internal;
     int ret = 0;
 
     /* if the decoder init function was already called previously,
@@ -1605,6 +1606,13 @@ FF_ENABLE_DEPRECATION_WARNINGS
         avctx->export_side_data |= AV_CODEC_EXPORT_DATA_MVS;
     }
 
+    avci->in_pkt         = av_packet_alloc();
+    avci->last_pkt_props = av_packet_alloc();
+    avci->pkt_props      = av_fifo_alloc2(1, sizeof(*avci->last_pkt_props),
+                                          AV_FIFO_FLAG_AUTO_GROW);
+    if (!avci->in_pkt || !avci->last_pkt_props || !avci->pkt_props)
+        return AVERROR(ENOMEM);
+
     ret = decode_bsfs_init(avctx);
     if (ret < 0)
         return ret;