h264: fix the check for mixed IDR/non-IDR slices

libavcodec/h264_slice.c

@@ -1333,6 +1333,8 @@ static int h264_field_start(H264Context *h, const H264SliceContext *sl,
     h->nb_mmco = sl->nb_mmco;
     h->explicit_ref_marking = sl->explicit_ref_marking;
 
+    h->picture_idr = nal->type == H264_NAL_IDR_SLICE;
+
     /* Set the frame properties/side data. Only done for the second field in
      * field coded frames, since some SEI information is present for each field
      * and is merged by the SEI parsing code. */
@@ -1599,6 +1601,11 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl,
         }
     }
 
+    if (h->picture_idr && nal->type != H264_NAL_IDR_SLICE) {
+        av_log(h->avctx, AV_LOG_ERROR, "Invalid mix of IDR and non-IDR slices\n");
+        return AVERROR_INVALIDDATA;
+    }
+
     assert(h->mb_num == h->mb_width * h->mb_height);
     if (sl->first_mb_addr << FIELD_OR_MBAFF_PICTURE(h) >= h->mb_num ||
         sl->first_mb_addr >= h->mb_num) {

libavcodec/h264dec.c

@@ -694,12 +694,6 @@ static int decode_nal_units(H264Context *h, const uint8_t *buf, int buf_size)
         err = 0;
         switch (nal->type) {
         case H264_NAL_IDR_SLICE:
-            if (nal->type != H264_NAL_IDR_SLICE) {
-                av_log(h->avctx, AV_LOG_ERROR,
-                       "Invalid mix of idr and non-idr slices\n");
-                ret = -1;
-                goto end;
-            }
             idr(h); // FIXME ensure we don't lose some frames if there is reordering
         case H264_NAL_SLICE:
             sl->gb = nal->gb;

libavcodec/h264dec.h

@@ -366,6 +366,11 @@ typedef struct H264Context {
      */
     int postpone_filter;
 
+    /*
+     * Set to 1 when the current picture is IDR, 0 otherwise.
+     */
+    int picture_idr;
+
     int8_t(*intra4x4_pred_mode);
     H264PredContext hpc;