cbs: ff_cbs_delete_unit: Replace return value with assert

ff_cbs_delete_unit never fails if the index of the unit to delete is
valid, as it is with all current callers of the function. So just assert
in ff_cbs_delete_unit that the index is valid and change the return
value to void in order to remove the callers' checks for whether
ff_cbs_delete_unit failed.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>

libavcodec/av1_metadata_bsf.c

@@ -167,13 +167,8 @@ static int av1_metadata_filter(AVBSFContext *bsf, AVPacket *pkt)
 
     if (ctx->delete_padding) {
         for (i = frag->nb_units - 1; i >= 0; i--) {
-            if (frag->units[i].type == AV1_OBU_PADDING) {
-                err = ff_cbs_delete_unit(ctx->cbc, frag, i);
-                if (err < 0) {
-                    av_log(bsf, AV_LOG_ERROR, "Failed to delete Padding OBU.\n");
-                    goto fail;
-                }
-            }
+            if (frag->units[i].type == AV1_OBU_PADDING)
+                ff_cbs_delete_unit(ctx->cbc, frag, i);
         }
     }
 

libavcodec/cbs.c

@@ -737,12 +737,12 @@ int ff_cbs_insert_unit_data(CodedBitstreamContext *ctx,
     return 0;
 }
 
-int ff_cbs_delete_unit(CodedBitstreamContext *ctx,
-                       CodedBitstreamFragment *frag,
-                       int position)
+void ff_cbs_delete_unit(CodedBitstreamContext *ctx,
+                        CodedBitstreamFragment *frag,
+                        int position)
 {
-    if (position < 0 || position >= frag->nb_units)
-        return AVERROR(EINVAL);
+    av_assert0(0 <= position && position < frag->nb_units
+                             && "Unit to be deleted not in fragment.");
 
     cbs_unit_uninit(ctx, &frag->units[position]);
 
@@ -752,6 +752,4 @@ int ff_cbs_delete_unit(CodedBitstreamContext *ctx,
         memmove(frag->units + position,
                 frag->units + position + 1,
                 (frag->nb_units - position) * sizeof(*frag->units));
-
-    return 0;
 }

libavcodec/cbs.h

@@ -380,10 +380,12 @@ int ff_cbs_insert_unit_data(CodedBitstreamContext *ctx,
 
 /**
  * Delete a unit from a fragment and free all memory it uses.
+ *
+ * Requires position to be >= 0 and < frag->nb_units.
  */
-int ff_cbs_delete_unit(CodedBitstreamContext *ctx,
-                       CodedBitstreamFragment *frag,
-                       int position);
+void ff_cbs_delete_unit(CodedBitstreamContext *ctx,
+                        CodedBitstreamFragment *frag,
+                        int position);
 
 
 #endif /* AVCODEC_CBS_H */

libavcodec/cbs_h2645.c

@@ -1664,7 +1664,7 @@ int ff_cbs_h264_delete_sei_message(CodedBitstreamContext *ctx,
         }
         av_assert0(i < au->nb_units && "NAL unit not in access unit.");
 
-        return ff_cbs_delete_unit(ctx, au, i);
+        ff_cbs_delete_unit(ctx, au, i);
     } else {
         cbs_h264_free_sei_payload(&sei->payload[position]);
 
@@ -1672,7 +1672,7 @@ int ff_cbs_h264_delete_sei_message(CodedBitstreamContext *ctx,
         memmove(sei->payload + position,
                 sei->payload + position + 1,
                 (sei->payload_count - position) * sizeof(*sei->payload));
-
-        return 0;
     }
+
+    return 0;
 }

libavcodec/h264_metadata_bsf.c

@@ -427,13 +427,7 @@ static int h264_metadata_filter(AVBSFContext *bsf, AVPacket *pkt)
     if (ctx->delete_filler) {
         for (i = au->nb_units - 1; i >= 0; i--) {
             if (au->units[i].type == H264_NAL_FILLER_DATA) {
-                // Filler NAL units.
-                err = ff_cbs_delete_unit(ctx->cbc, au, i);
-                if (err < 0) {
-                    av_log(bsf, AV_LOG_ERROR, "Failed to delete "
-                           "filler NAL.\n");
-                    goto fail;
-                }
+                ff_cbs_delete_unit(ctx->cbc, au, i);
                 continue;
             }
 

libavcodec/h264_redundant_pps_bsf.c

@@ -94,9 +94,7 @@ static int h264_redundant_pps_filter(AVBSFContext *bsf, AVPacket *pkt)
             if (!au_has_sps) {
                 av_log(bsf, AV_LOG_VERBOSE, "Deleting redundant PPS "
                        "at %"PRId64".\n", pkt->pts);
-                err = ff_cbs_delete_unit(ctx->input, au, i);
-                if (err < 0)
-                    goto fail;
+                ff_cbs_delete_unit(ctx->input, au, i);
                 i--;
                 continue;
             }