h264_parser: Fix POC parsing for the case where MMCO_RESET is present.

Signed-off-by: Anton Khirnov <anton@khirnov.net>

1 files changed, 102 insertions, 8 deletions

diff --git a/libavcodec/h264_parser.c b/libavcodec/h264_parser.c
index 75e09f400d..e6e27042fd 100644
--- a/libavcodec/h264_parser.c
+++ b/libavcodec/h264_parser.c
@@ -87,6 +87,75 @@ found:
     return i - (state & 5);
 }
 
+static int scan_mmco_reset(AVCodecParserContext *s)
+{
+    H264Context *h = s->priv_data;
+
+    h->slice_type_nos = s->pict_type & 3;
+
+    if (h->pps.redundant_pic_cnt_present)
+        get_ue_golomb(&h->gb); // redundant_pic_count
+
+    if (ff_set_ref_count(h) < 0)
+        return AVERROR_INVALIDDATA;
+
+    if (h->slice_type_nos != AV_PICTURE_TYPE_I) {
+        int list;
+        for (list = 0; list < h->list_count; list++) {
+            if (get_bits1(&h->gb)) {
+                int index;
+                for (index = 0; ; index++) {
+                    unsigned int reordering_of_pic_nums_idc = get_ue_golomb_31(&h->gb);
+
+                    if (reordering_of_pic_nums_idc < 3)
+                        get_ue_golomb(&h->gb);
+                    else if (reordering_of_pic_nums_idc > 3) {
+                        av_log(h->avctx, AV_LOG_ERROR,
+                               "illegal reordering_of_pic_nums_idc %d\n",
+                               reordering_of_pic_nums_idc);
+                        return AVERROR_INVALIDDATA;
+                    } else
+                        break;
+
+                    if (index >= h->ref_count[list]) {
+                        av_log(h->avctx, AV_LOG_ERROR, "reference count overflow\n");
+                        return AVERROR_INVALIDDATA;
+                    }
+                }
+            }
+        }
+    }
+
+    if ((h->pps.weighted_pred && h->slice_type_nos == AV_PICTURE_TYPE_P) ||
+        (h->pps.weighted_bipred_idc == 1 && h->slice_type_nos == AV_PICTURE_TYPE_B))
+        ff_pred_weight_table(h);
+
+    if (get_bits1(&h->gb)) { // adaptive_ref_pic_marking_mode_flag
+        int i;
+        for (i = 0; i < MAX_MMCO_COUNT; i++) {
+            MMCOOpcode opcode = get_ue_golomb_31(&h->gb);
+            if (opcode > (unsigned) MMCO_LONG) {
+                av_log(h->avctx, AV_LOG_ERROR,
+                       "illegal memory management control operation %d\n",
+                       opcode);
+                return AVERROR_INVALIDDATA;
+            }
+            if (opcode == MMCO_END)
+               return 0;
+            else if (opcode == MMCO_RESET)
+                return 1;
+
+            if (opcode == MMCO_SHORT2UNUSED || opcode == MMCO_SHORT2LONG)
+                get_ue_golomb(&h->gb);
+            if (opcode == MMCO_SHORT2LONG || opcode == MMCO_LONG2UNUSED ||
+                opcode == MMCO_LONG || opcode == MMCO_SET_MAX_LONG)
+                get_ue_golomb_31(&h->gb);
+        }
+    }
+
+    return 0;
+}
+
 /**
  * Parse NAL units of found picture and decode some basic information.
  *
@@ -103,7 +172,7 @@ static inline int parse_nal_units(AVCodecParserContext *s,
     const uint8_t *buf_end = buf + buf_size;
     unsigned int pps_id;
     unsigned int slice_type;
-    int state = -1;
+    int state = -1, got_reset = 0;
     const uint8_t *ptr;
     int field_poc[2];
 
@@ -132,8 +201,16 @@ static inline int parse_nal_units(AVCodecParserContext *s,
         case NAL_SLICE:
         case NAL_IDR_SLICE:
             // Do not walk the whole buffer just to decode slice header
-            if (src_length > 60)
-                src_length = 60;
+            if (state & 0x1f == NAL_IDR_SLICE || (state >> 5) & 0x3 == 0) {
+                /* IDR or disposable slice
+                 * No need to decode many bytes because MMCOs shall not be present. */
+                if (src_length > 60)
+                    src_length = 60;
+            } else {
+                /* To decode up to MMCOs */
+                if (src_length > 1000)
+                    src_length = 1000;
+            }
             break;
         }
         ptr = ff_h264_decode_nal(h, buf, &dst_length, &consumed, src_length);
@@ -219,16 +296,33 @@ static inline int parse_nal_units(AVCodecParserContext *s,
                     h->delta_poc[1] = get_se_golomb(&h->gb);
             }
 
-            /* Decode POC of this picture. */
+            /* Decode POC of this picture.
+             * The prev_ values needed for decoding POC of the next picture are not set here. */
             field_poc[0] = field_poc[1] = INT_MAX;
             ff_init_poc(h, field_poc, &s->output_picture_number);
 
+            /* Continue parsing to check if MMCO_RESET is present.
+             * FIXME: MMCO_RESET could appear in non-first slice.
+             *        Maybe, we should parse all undisposable non-IDR slice of this
+             *        picture until encountering MMCO_RESET in a slice of it. */
+            if (h->nal_ref_idc && h->nal_unit_type != NAL_IDR_SLICE) {
+                got_reset = scan_mmco_reset(s);
+                if (got_reset < 0)
+                    return got_reset;
+            }
+
             /* Set up the prev_ values for decoding POC of the next picture. */
-            h->prev_frame_num        = h->frame_num;
-            h->prev_frame_num_offset = h->frame_num_offset;
+            h->prev_frame_num        = got_reset ? 0 : h->frame_num;
+            h->prev_frame_num_offset = got_reset ? 0 : h->frame_num_offset;
             if (h->nal_ref_idc != 0) {
-                h->prev_poc_msb = h->poc_msb;
-                h->prev_poc_lsb = h->poc_lsb;
+                if (!got_reset) {
+                    h->prev_poc_msb = h->poc_msb;
+                    h->prev_poc_lsb = h->poc_lsb;
+                } else {
+                    h->prev_poc_msb = 0;
+                    h->prev_poc_lsb =
+                        h->picture_structure == PICT_BOTTOM_FIELD ? 0 : field_poc[0];
+                }
             }
 
             if (h->sps.pic_struct_present_flag) {