diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index 9fe3a16db7..e0819f4515 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -1920,6 +1920,8 @@ int attribute_align_arg avcodec_decode_video2(AVCodecContext *avctx, AVFrame *pi
     // copy to ensure we do not change avpkt
     AVPacket tmp = *avpkt;
 
+    if (!avctx->codec)
+        return AVERROR(EINVAL);
     if (avctx->codec->type != AVMEDIA_TYPE_VIDEO) {
         av_log(avctx, AV_LOG_ERROR, "Invalid media type for video\n");
         return AVERROR(EINVAL);
diff --git a/libavformat/cafenc.c b/libavformat/cafenc.c
index 11bb055965..cd3a0be907 100644
--- a/libavformat/cafenc.c
+++ b/libavformat/cafenc.c
@@ -86,8 +86,9 @@ static uint32_t samples_per_packet(enum AVCodecID codec_id, int channels) {
         return 1152;
     case AV_CODEC_ID_AC3:
         return 1536;
-    case AV_CODEC_ID_ALAC:
     case AV_CODEC_ID_QDM2:
+        return 2048 * channels;
+    case AV_CODEC_ID_ALAC:
         return 4096;
     case AV_CODEC_ID_ADPCM_IMA_WAV:
         return (1024 - 4 * channels) * 8 / (4 * channels) + 1;
diff --git a/libavformat/mov.c b/libavformat/mov.c
index 5c61f6c718..36b17c1710 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -1551,6 +1551,7 @@ int ff_mov_read_stsd_entries(MOVContext *c, AVIOContext *pb, int entries)
     case AV_CODEC_ID_ILBC:
     case AV_CODEC_ID_MACE3:
     case AV_CODEC_ID_MACE6:
+    case AV_CODEC_ID_QDM2:
         st->codec->block_align = sc->bytes_per_frame;
         break;
     case AV_CODEC_ID_ALAC: