Merge commit '54dd9b1cdd9e54f1ee39ae25af0324f8aba2831b'

* commit '54dd9b1cdd9e54f1ee39ae25af0324f8aba2831b':
  h264: set mb_aff_frame in frame_start()
  h264: move the block starting a new field out of slice_header_parse()

Both commits are merged at the same time in order to prevent a
regression with Ticket #4440 (see 38660128).

Merged-by: Clément Bœsch <u@pkh.me>

diff --cc libavcodec/h264_slice.c
index ee7dedbe2d744b6cbd1a3e07bc0be235526e87b9,4b0adab11037371e9bc10c764e5cada6c1d8e329..befea2aea14faed3379ec8b4781b3e1c57a0c8a8
--- 1/libavcodec/h264_slice.c
--- 2/libavcodec/h264_slice.c
+++ b/libavcodec/h264_slice.c
@@@ -385,10 -377,8 +385,11 @@@ int ff_h264_update_thread_context(AVCod
      h->coded_picture_number = h1->coded_picture_number;
      h->first_field          = h1->first_field;
      h->picture_structure    = h1->picture_structure;
+     h->mb_aff_frame         = h1->mb_aff_frame;
      h->droppable            = h1->droppable;
 +    h->backup_width         = h1->backup_width;
 +    h->backup_height        = h1->backup_height;
 +    h->backup_pix_fmt       = h1->backup_pix_fmt;
  
      for (i = 0; i < H264_MAX_PICTURE_COUNT; i++) {
          ff_h264_unref_picture(h, &h->DPB[i]);
@@@ -1335,60 -1175,10 +1338,14 @@@ static int h264_slice_header_parse(H264
      int ret;
      unsigned int slice_type, tmp, i;
      int field_pic_flag, bottom_field_flag;
 -    int frame_num, droppable, picture_structure;
 +    int first_slice = sl == h->slice_ctx && !h->current_slice;
-     int frame_num, droppable, picture_structure;
-     int mb_aff_frame, last_mb_aff_frame;
++    int frame_num, picture_structure;
 +
 +    if (first_slice)
 +        av_assert0(!h->setup_finished);
  
 -    sl->first_mb_addr = get_ue_golomb(&sl->gb);
 +    sl->first_mb_addr = get_ue_golomb_long(&sl->gb);
  
-     if (sl->first_mb_addr == 0) { // FIXME better field boundary detection
-         if (h->current_slice) {
-             if (h->setup_finished) {
-                 av_log(h->avctx, AV_LOG_ERROR, "Too many fields\n");
-                 return AVERROR_INVALIDDATA;
-             }
-             if (h->max_contexts > 1) {
-                 if (!h->single_decode_warning) {
-                     av_log(h->avctx, AV_LOG_WARNING, "Cannot decode multiple access units as slice threads\n");
-                     h->single_decode_warning = 1;
-                 }
-                 h->max_contexts = 1;
-                 return SLICE_SINGLETHREAD;
-             }
- 
-             if (h->cur_pic_ptr && FIELD_PICTURE(h) && h->first_field) {
-                 ret = ff_h264_field_end(h, h->slice_ctx, 1);
-                 h->current_slice = 0;
-                 if (ret < 0)
-                     return ret;
-             } else if (h->cur_pic_ptr && !FIELD_PICTURE(h) && !h->first_field && h->nal_unit_type  == NAL_IDR_SLICE) {
-                 av_log(h, AV_LOG_WARNING, "Broken frame packetizing\n");
-                 ret = ff_h264_field_end(h, h->slice_ctx, 1);
-                 h->current_slice = 0;
-                 ff_thread_report_progress(&h->cur_pic_ptr->tf, INT_MAX, 0);
-                 ff_thread_report_progress(&h->cur_pic_ptr->tf, INT_MAX, 1);
-                 h->cur_pic_ptr = NULL;
-                 if (ret < 0)
-                     return ret;
-             } else
-                 return AVERROR_INVALIDDATA;
-         }
- 
-         if (!h->first_field) {
-             if (h->cur_pic_ptr && !h->droppable) {
-                 ff_thread_report_progress(&h->cur_pic_ptr->tf, INT_MAX,
-                                           h->picture_structure == PICT_BOTTOM_FIELD);
-             }
-             h->cur_pic_ptr = NULL;
-         }
-     }
- 
-     if (!h->current_slice)
-         av_assert0(sl == h->slice_ctx);
- 
      slice_type = get_ue_golomb_31(&sl->gb);
      if (slice_type > 9) {
          av_log(h->avctx, AV_LOG_ERROR,
@@@ -1442,20 -1220,6 +1388,7 @@@
                 "non-existing SPS %u referenced\n", pps->sps_id);
          return AVERROR_INVALIDDATA;
      }
-     if (!first_slice) {
-         if (h->ps.pps->sps_id != pps->sps_id ||
-             h->ps.pps->transform_8x8_mode != pps->transform_8x8_mode /*||
-             (h->setup_finished && h->ps.pps != pps)*/) {
-             av_log(h->avctx, AV_LOG_ERROR, "PPS changed between slices\n");
-             return AVERROR_INVALIDDATA;
-         }
-         if (h->ps.sps != (const SPS*)h->ps.sps_list[h->ps.pps->sps_id]->data) {
-             av_log(h->avctx, AV_LOG_ERROR,
-                "SPS changed in the middle of the frame\n");
-             return AVERROR_INVALIDDATA;
-         }
-     }
 +
      sps = (const SPS*)h->ps.sps_list[pps->sps_id]->data;
  
      frame_num = get_bits(&sl->gb, sps->log2_max_frame_num);
@@@ -1471,10 -1227,8 +1404,7 @@@
          h->poc.frame_num = frame_num;
  
      sl->mb_mbaff       = 0;
-     mb_aff_frame       = 0;
-     last_mb_aff_frame  = h->mb_aff_frame;
  
--    droppable = nal->ref_idc == 0;
      if (sps->frame_mbs_only_flag) {
          picture_structure = PICT_FRAME;
      } else {
@@@ -1489,29 -1238,8 +1419,9 @@@
              picture_structure = PICT_TOP_FIELD + bottom_field_flag;
          } else {
              picture_structure = PICT_FRAME;
-             mb_aff_frame      = sps->mb_aff;
-         }
-     }
- 
-     if (h->current_slice) {
-         if (h->picture_structure != picture_structure ||
-             h->droppable         != droppable ||
-             last_mb_aff_frame  != mb_aff_frame) {
-             av_log(h->avctx, AV_LOG_ERROR,
-                    "Changing field mode (%d -> %d) between slices is not allowed\n",
-                    h->picture_structure, picture_structure);
-             return AVERROR_INVALIDDATA;
-         } else if (!h->cur_pic_ptr) {
-             av_log(h->avctx, AV_LOG_ERROR,
-                    "unset cur_pic_ptr on slice %d\n",
-                    h->current_slice + 1);
-             return AVERROR_INVALIDDATA;
          }
      }
-     if (!h->setup_finished) {
-         h->mb_aff_frame      = mb_aff_frame;
-     }
 +
      sl->picture_structure      = picture_structure;
      sl->mb_field_decoding_flag = picture_structure != PICT_FRAME;
  
@@@ -1660,19 -1388,51 +1570,104 @@@ int ff_h264_decode_slice_header(H264Con
                                  const H2645NAL *nal)
  {
      int i, j, ret = 0;
 +    int first_slice = sl == h->slice_ctx && !h->current_slice;
  
      ret = h264_slice_header_parse(h, sl, nal);
-     if (ret) // can not be ret<0 because of SLICE_SKIPED, SLICE_SINGLETHREAD, ...
+     if (ret < 0)
          return ret;
  
 -        if (h->current_slice && h->cur_pic_ptr && FIELD_PICTURE(h)) {
 -            ff_h264_field_end(h, sl, 1);
+     if (sl->first_mb_addr == 0) { // FIXME better field boundary detection
 -        h->current_slice = 0;
++        if (h->current_slice) {
++            if (h->setup_finished) {
++                av_log(h->avctx, AV_LOG_ERROR, "Too many fields\n");
++                return AVERROR_INVALIDDATA;
++            }
++            if (h->max_contexts > 1) {
++                if (!h->single_decode_warning) {
++                    av_log(h->avctx, AV_LOG_WARNING, "Cannot decode multiple access units as slice threads\n");
++                    h->single_decode_warning = 1;
++                }
++                h->max_contexts = 1;
++                return SLICE_SINGLETHREAD;
++            }
++
++            if (h->cur_pic_ptr && FIELD_PICTURE(h) && h->first_field) {
++                ret = ff_h264_field_end(h, h->slice_ctx, 1);
++                h->current_slice = 0;
++                if (ret < 0)
++                    return ret;
++            } else if (h->cur_pic_ptr && !FIELD_PICTURE(h) && !h->first_field && h->nal_unit_type  == NAL_IDR_SLICE) {
++                av_log(h, AV_LOG_WARNING, "Broken frame packetizing\n");
++                ret = ff_h264_field_end(h, h->slice_ctx, 1);
++                h->current_slice = 0;
++                ff_thread_report_progress(&h->cur_pic_ptr->tf, INT_MAX, 0);
++                ff_thread_report_progress(&h->cur_pic_ptr->tf, INT_MAX, 1);
++                h->cur_pic_ptr = NULL;
++                if (ret < 0)
++                    return ret;
++            } else
++                return AVERROR_INVALIDDATA;
+         }
+ 
 -    if (h->current_slice == 0) {
 -        ret = h264_field_start(h, sl, nal);
 -        if (ret < 0)
 -            return ret;
 -    } else {
 -        if (h->ps.pps != (const PPS*)h->ps.pps_list[sl->pps_id]->data) {
+         if (!h->first_field) {
+             if (h->cur_pic_ptr && !h->droppable) {
+                 ff_thread_report_progress(&h->cur_pic_ptr->tf, INT_MAX,
+                                           h->picture_structure == PICT_BOTTOM_FIELD);
+             }
+             h->cur_pic_ptr = NULL;
+         }
+     }
+ 
++    if (!h->current_slice)
++        av_assert0(sl == h->slice_ctx);
++
++    if (h->current_slice == 0 && !h->first_field) {
++        if (
++            (h->avctx->skip_frame >= AVDISCARD_NONREF && !h->nal_ref_idc) ||
++            (h->avctx->skip_frame >= AVDISCARD_BIDIR  && sl->slice_type_nos == AV_PICTURE_TYPE_B) ||
++            (h->avctx->skip_frame >= AVDISCARD_NONINTRA && sl->slice_type_nos != AV_PICTURE_TYPE_I) ||
++            (h->avctx->skip_frame >= AVDISCARD_NONKEY && h->nal_unit_type != NAL_IDR_SLICE && h->sei.recovery_point.recovery_frame_cnt < 0) ||
++            h->avctx->skip_frame >= AVDISCARD_ALL) {
++            return SLICE_SKIPED;
++        }
++    }
++
++    if (!first_slice) {
++        const PPS *pps = (const PPS*)h->ps.pps_list[sl->pps_id]->data;
++
++        if (h->ps.pps->sps_id != pps->sps_id ||
++            h->ps.pps->transform_8x8_mode != pps->transform_8x8_mode /*||
++            (h->setup_finished && h->ps.pps != pps)*/) {
+             av_log(h->avctx, AV_LOG_ERROR, "PPS changed between slices\n");
+             return AVERROR_INVALIDDATA;
+         }
++        if (h->ps.sps != (const SPS*)h->ps.sps_list[h->ps.pps->sps_id]->data) {
++            av_log(h->avctx, AV_LOG_ERROR,
++               "SPS changed in the middle of the frame\n");
++            return AVERROR_INVALIDDATA;
++        }
++    }
+ 
 +    if (h->current_slice == 0) {
 +        ret = h264_field_start(h, sl, nal, first_slice);
 +        if (ret < 0)
 +            return ret;
++    } else {
+         if (h->picture_structure != sl->picture_structure ||
+             h->droppable         != (nal->ref_idc == 0)) {
+             av_log(h->avctx, AV_LOG_ERROR,
+                    "Changing field mode (%d -> %d) between slices is not allowed\n",
+                    h->picture_structure, sl->picture_structure);
+             return AVERROR_INVALIDDATA;
+         } else if (!h->cur_pic_ptr) {
+             av_log(h->avctx, AV_LOG_ERROR,
+                    "unset cur_pic_ptr on slice %d\n",
+                    h->current_slice + 1);
+             return AVERROR_INVALIDDATA;
+         }
      }
  
 -    assert(h->mb_num == h->mb_width * h->mb_height);
 +    av_assert1(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) {
          av_log(h->avctx, AV_LOG_ERROR, "first_mb_in_slice overflow\n");