diff --git a/libavcodec/internal.h b/libavcodec/internal.h
index fc906322f8..500511dada 100644
--- a/libavcodec/internal.h
+++ b/libavcodec/internal.h
@@ -46,7 +46,13 @@
  * all.
  */
 #define FF_CODEC_CAP_INIT_CLEANUP           (1 << 1)
-
+/**
+ * Decoders marked with FF_CODEC_CAP_SETS_PKT_DTS want to set
+ * AVFrame.pkt_dts manually. If the flag is set, utils.c won't overwrite
+ * this field. If it's unset, utils.c tries to guess the pkt_dts field
+ * from the input AVPacket.
+ */
+#define FF_CODEC_CAP_SETS_PKT_DTS           (1 << 2)
 
 #ifdef DEBUG
 #   define ff_dlog(ctx, ...) av_log(ctx, AV_LOG_DEBUG, __VA_ARGS__)
diff --git a/libavcodec/mmaldec.c b/libavcodec/mmaldec.c
index f4bf9214fe..a23a97fcfa 100644
--- a/libavcodec/mmaldec.c
+++ b/libavcodec/mmaldec.c
@@ -792,6 +792,7 @@ AVCodec ff_h264_mmal_decoder = {
     .flush          = ffmmal_flush,
     .priv_class     = &ffmmaldec_class,
     .capabilities   = AV_CODEC_CAP_DELAY,
+    .caps_internal  = FF_CODEC_CAP_SETS_PKT_DTS,
     .pix_fmts       = (const enum AVPixelFormat[]) { AV_PIX_FMT_MMAL,
                                                      AV_PIX_FMT_YUV420P,
                                                      AV_PIX_FMT_NONE},
diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index 1d718b288c..a94e4a6058 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -1482,7 +1482,8 @@ int attribute_align_arg avcodec_decode_video2(AVCodecContext *avctx, AVFrame *pi
         else {
             ret = avctx->codec->decode(avctx, picture, got_picture_ptr,
                                        avpkt);
-            picture->pkt_dts = avpkt->dts;
+            if (!(avctx->codec->caps_internal & FF_CODEC_CAP_SETS_PKT_DTS))
+                picture->pkt_dts = avpkt->dts;
             /* get_buffer is supposed to set frame parameters */
             if (!(avctx->codec->capabilities & AV_CODEC_CAP_DR1)) {
                 picture->sample_aspect_ratio = avctx->sample_aspect_ratio;