ffmpeg bsf h264 metadata restore 0 at end of nalus

$ git diff libavcodec/cbs_h2645.c
diff --git a/libavcodec/cbs_h2645.c b/libavcodec/cbs_h2645.c
index 80e48829af..30e213a289 100644
--- a/libavcodec/cbs_h2645.c
+++ b/libavcodec/cbs_h2645.c
@@ -726,7 +726,6 @@ static int cbs_h264_read_nal_unit(CodedBitstreamContext *ctx,
     case H264_NAL_PPS:
         {
             H264RawPPS *pps = unit->content;
-
             err = cbs_h264_read_pps(ctx, &gbc, pps);
             if (err < 0)
                 return err;
@@ -1244,7 +1243,8 @@ static int cbs_h2645_assemble_fragment(CodedBitstreamContext *ctx,
     max_size = 0;
     for (i = 0; i < frag->nb_units; i++) {
         // Start code + content with worst-case emulation prevention.
-        max_size += 4 + frag->units[i].data_size * 3 / 2;
+        //max_size += 4 + frag->units[i].data_size * 3 / 2;
+               max_size += 4 + frag->units[i].data_size + 1000000; //emcodem: todo: calculate max_data_size correctly
     }

     data = av_realloc(NULL, max_size + AV_INPUT_BUFFER_PADDING_SIZE);
@@ -1273,6 +1273,7 @@ static int cbs_h2645_assemble_fragment(CodedBitstreamContext *ctx,
         data[dp++] = 1;

         zero_run = 0;
+
         for (sp = 0; sp < unit->data_size; sp++) {
             if (zero_run < 2) {
                 if (unit->data[sp] == 0)
@@ -1287,8 +1288,16 @@ static int cbs_h2645_assemble_fragment(CodedBitstreamContext *ctx,
                 zero_run = unit->data[sp] == 0;
             }
             data[dp++] = unit->data[sp];
+
         }
+
+               //emcodem: example adding 1000 bytes to each and every NAL
+               //you can e.g. check unit->type here and pad sps and or pps accordingly.
+               //example: count bytes until first slice is there and if slice is there, prepend it with missing bytes until 77824 was reached.
+               //77824 is found to be start of first slice in each and every xavc file
+               dp += 1000;
     }
+

     av_assert0(dp <= max_size);
     err = av_reallocp(&data, dp + AV_INPUT_BUFFER_PADDING_SIZE);