h264parse: Fix multiple SEI messages in one SEI RBSP parsing.

An SEI RBSP could contains more than one SEI message as specified in
7.4.2.3.1.

This commit change the parser API: the gst_h264_parser_parse_sei()
function now create and fill a GArray containing GstH264SEIMessage.

https://bugzilla.gnome.org/show_bug.cgi?id=721715

gst-libs/gst/codecparsers/gsth264parser.c

@@ -269,6 +269,21 @@ nal_reader_skip (NalReader * nr, guint nbits)
   return TRUE;
 }
 
+static inline gboolean
+nal_reader_skip_to_next_byte (NalReader * nr)
+{
+  if (nr->bits_in_cache == 0) {
+    if (G_LIKELY ((nr->size - nr->byte) > 0))
+      nr->byte++;
+    else
+      return FALSE;
+  }
+
+  nr->bits_in_cache = 0;
+
+  return TRUE;
+}
+
 static inline guint
 nal_reader_get_pos (const NalReader * nr)
 {
@@ -490,6 +505,14 @@ scan_for_start_codes (const guint8 * data, guint size)
       0, size);
 }
 
+static gboolean
+gst_h264_parser_byte_aligned (NalReader * nr)
+{
+  if (nr->bits_in_cache != 0)
+    return FALSE;
+  return TRUE;
+}
+
 static gboolean
 gst_h264_parser_more_data (NalReader * nr)
 {
@@ -1145,6 +1168,80 @@ error:
   return GST_H264_PARSER_ERROR;
 }
 
+static GstH264ParserResult
+gst_h264_parser_parse_sei_message (GstH264NalParser * nalparser,
+    NalReader * nr, GstH264SEIMessage * sei)
+{
+  guint32 payloadSize;
+  guint8 payload_type_byte, payload_size_byte;
+#ifndef GST_DISABLE_GST_DEBUG
+  guint remaining, payload_size;
+#endif
+  GstH264ParserResult res;
+
+  GST_DEBUG ("parsing \"Sei message\"");
+
+  sei->payloadType = 0;
+  do {
+    READ_UINT8 (nr, payload_type_byte, 8);
+    sei->payloadType += payload_type_byte;
+  } while (payload_type_byte == 0xff);
+
+  payloadSize = 0;
+  do {
+    READ_UINT8 (nr, payload_size_byte, 8);
+    payloadSize += payload_size_byte;
+  }
+  while (payload_size_byte == 0xff);
+
+#ifndef GST_DISABLE_GST_DEBUG
+  remaining = nal_reader_get_remaining (nr);
+  payload_size = payloadSize * 8 < remaining ? payloadSize * 8 : remaining;
+
+  GST_DEBUG ("SEI message received: payloadType  %u, payloadSize = %u bits",
+      sei->payloadType, payload_size);
+#endif
+
+  if (sei->payloadType == GST_H264_SEI_BUF_PERIOD) {
+    /* size not set; might depend on emulation_prevention_three_byte */
+    res = gst_h264_parser_parse_buffering_period (nalparser,
+        &sei->payload.buffering_period, nr);
+  } else if (sei->payloadType == GST_H264_SEI_PIC_TIMING) {
+    /* size not set; might depend on emulation_prevention_three_byte */
+    res = gst_h264_parser_parse_pic_timing (nalparser,
+        &sei->payload.pic_timing, nr);
+  } else {
+    /* Just consume payloadSize */
+    guint32 i;
+    for (i = 0; i < payloadSize; i++)
+      nal_reader_skip_to_next_byte (nr);
+    res = GST_H264_PARSER_OK;
+  }
+
+  /* When SEI message doesn't end at byte boundary,
+   * check remaining bits fit the specification.
+   */
+  if (!gst_h264_parser_byte_aligned (nr)) {
+    guint8 bit_equal_to_one;
+    READ_UINT8 (nr, bit_equal_to_one, 1);
+    if (!bit_equal_to_one)
+      GST_WARNING ("Bit non equal to one.");
+
+    while (!gst_h264_parser_byte_aligned (nr)) {
+      guint8 bit_equal_to_zero;
+      READ_UINT8 (nr, bit_equal_to_zero, 1);
+      if (bit_equal_to_zero)
+        GST_WARNING ("Bit non equal to zero.");
+    }
+  }
+
+  return res;
+
+error:
+  GST_WARNING ("error parsing \"Sei message\"");
+  return GST_H264_PARSER_ERROR;
+}
+
 /******** API *************/
 
 /**
@@ -1942,69 +2039,33 @@ error:
  * gst_h264_parser_parse_sei:
  * @nalparser: a #GstH264NalParser
  * @nalu: The #GST_H264_NAL_SEI #GstH264NalUnit to parse
- * @sei: The #GstH264SEIMessage to fill.
+ * @messages: The GArray of #GstH264SEIMessage to fill. The caller must free it when done.
  *
- * Parses @data, and fills the @sei structures.
+ * Parses @data, create and fills the @messages array.
  *
  * Returns: a #GstH264ParserResult
  */
 GstH264ParserResult
 gst_h264_parser_parse_sei (GstH264NalParser * nalparser, GstH264NalUnit * nalu,
-    GstH264SEIMessage * sei)
+    GArray ** messages)
 {
   NalReader nr;
-
-  guint32 payloadSize;
-  guint8 payload_type_byte, payload_size_byte;
-#ifndef GST_DISABLE_GST_DEBUG
-  guint remaining, payload_size;
-#endif
+  GstH264SEIMessage sei;
   GstH264ParserResult res;
 
-  GST_DEBUG ("parsing \"Sei message\"");
-
+  GST_DEBUG ("parsing SEI nal");
   nal_reader_init (&nr, nalu->data + nalu->offset + 1, nalu->size - 1);
+  *messages = g_array_new (FALSE, FALSE, sizeof (GstH264SEIMessage));
 
-  /* init */
-  memset (sei, 0, sizeof (*sei));
-
-  sei->payloadType = 0;
   do {
-    READ_UINT8 (&nr, payload_type_byte, 8);
-    sei->payloadType += payload_type_byte;
-  } while (payload_type_byte == 0xff);
-
-  payloadSize = 0;
-  do {
-    READ_UINT8 (&nr, payload_size_byte, 8);
-    payloadSize += payload_size_byte;
-  }
-  while (payload_size_byte == 0xff);
-
-#ifndef GST_DISABLE_GST_DEBUG
-  remaining = nal_reader_get_remaining (&nr) * 8;
-  payload_size = payloadSize < remaining ? payloadSize : remaining;
-
-  GST_DEBUG ("SEI message received: payloadType  %u, payloadSize = %u bytes",
-      sei->payloadType, payload_size);
-#endif
-
-  if (sei->payloadType == GST_H264_SEI_BUF_PERIOD) {
-    /* size not set; might depend on emulation_prevention_three_byte */
-    res = gst_h264_parser_parse_buffering_period (nalparser,
-        &sei->payload.buffering_period, &nr);
-  } else if (sei->payloadType == GST_H264_SEI_PIC_TIMING) {
-    /* size not set; might depend on emulation_prevention_three_byte */
-    res = gst_h264_parser_parse_pic_timing (nalparser,
-        &sei->payload.pic_timing, &nr);
-  } else
-    res = GST_H264_PARSER_OK;
+    res = gst_h264_parser_parse_sei_message (nalparser, &nr, &sei);
+    if (res == GST_H264_PARSER_OK)
+      g_array_append_val (*messages, sei);
+    else
+      break;
+  } while (gst_h264_parser_more_data (&nr));
 
   return res;
-
-error:
-  GST_WARNING ("error parsing \"Sei message\"");
-  return GST_H264_PARSER_ERROR;
 }
 
 /**

gst-libs/gst/codecparsers/gsth264parser.h

@@ -749,7 +749,7 @@ GstH264ParserResult gst_h264_parser_parse_pps         (GstH264NalParser *nalpars
                                                        GstH264NalUnit *nalu, GstH264PPS *pps);
 
 GstH264ParserResult gst_h264_parser_parse_sei         (GstH264NalParser *nalparser,
-                                                       GstH264NalUnit *nalu, GstH264SEIMessage *sei);
+                                                       GstH264NalUnit *nalu, GArray ** messages);
 
 void gst_h264_nal_parser_free                         (GstH264NalParser *nalparser);
 

gst/videoparsers/gsth264parse.c

@@ -460,6 +460,50 @@ _nal_name (GstH264NalUnitType nal_type)
 }
 #endif
 
+static void
+gst_h264_parse_process_sei (GstH264Parse * h264parse, GstH264NalUnit * nalu)
+{
+  GstH264SEIMessage sei;
+  GstH264NalParser *nalparser = h264parse->nalparser;
+  GstH264ParserResult pres;
+  GArray *messages;
+  guint i;
+
+  pres = gst_h264_parser_parse_sei (nalparser, nalu, &messages);
+  if (pres != GST_H264_PARSER_OK)
+    GST_WARNING_OBJECT (h264parse, "failed to parse one ore more SEI message");
+
+  /* Even if pres != GST_H264_PARSER_OK, some message could have been parsed and
+   * stored in messages.
+   */
+  for (i = 0; i < messages->len; i++) {
+    sei = g_array_index (messages, GstH264SEIMessage, i);
+    switch (sei.payloadType) {
+      case GST_H264_SEI_PIC_TIMING:
+        h264parse->sei_pic_struct_pres_flag =
+            sei.payload.pic_timing.pic_struct_present_flag;
+        h264parse->sei_cpb_removal_delay =
+            sei.payload.pic_timing.cpb_removal_delay;
+        if (h264parse->sei_pic_struct_pres_flag)
+          h264parse->sei_pic_struct = sei.payload.pic_timing.pic_struct;
+        GST_LOG_OBJECT (h264parse, "pic timing updated");
+        break;
+      case GST_H264_SEI_BUF_PERIOD:
+        if (h264parse->ts_trn_nb == GST_CLOCK_TIME_NONE ||
+            h264parse->dts == GST_CLOCK_TIME_NONE)
+          h264parse->ts_trn_nb = 0;
+        else
+          h264parse->ts_trn_nb = h264parse->dts;
+
+        GST_LOG_OBJECT (h264parse,
+            "new buffering period; ts_trn_nb updated: %" GST_TIME_FORMAT,
+            GST_TIME_ARGS (h264parse->ts_trn_nb));
+        break;
+    }
+  }
+  g_array_free (messages, TRUE);
+}
+
 /* caller guarantees 2 bytes of nal payload */
 static void
 gst_h264_parse_process_nal (GstH264Parse * h264parse, GstH264NalUnit * nalu)
@@ -467,7 +511,6 @@ gst_h264_parse_process_nal (GstH264Parse * h264parse, GstH264NalUnit * nalu)
   guint nal_type;
   GstH264PPS pps = { 0, };
   GstH264SPS sps = { 0, };
-  GstH264SEIMessage sei;
   GstH264NalParser *nalparser = h264parse->nalparser;
   GstH264ParserResult pres;
 
@@ -528,28 +571,7 @@ gst_h264_parse_process_nal (GstH264Parse * h264parse, GstH264NalUnit * nalu)
       gst_h264_parser_store_nal (h264parse, pps.id, nal_type, nalu);
       break;
     case GST_H264_NAL_SEI:
-      gst_h264_parser_parse_sei (nalparser, nalu, &sei);
-      switch (sei.payloadType) {
-        case GST_H264_SEI_PIC_TIMING:
-          h264parse->sei_pic_struct_pres_flag =
-              sei.payload.pic_timing.pic_struct_present_flag;
-          h264parse->sei_cpb_removal_delay =
-              sei.payload.pic_timing.cpb_removal_delay;
-          if (h264parse->sei_pic_struct_pres_flag)
-            h264parse->sei_pic_struct = sei.payload.pic_timing.pic_struct;
-          break;
-        case GST_H264_SEI_BUF_PERIOD:
-          if (h264parse->ts_trn_nb == GST_CLOCK_TIME_NONE ||
-              h264parse->dts == GST_CLOCK_TIME_NONE)
-            h264parse->ts_trn_nb = 0;
-          else
-            h264parse->ts_trn_nb = h264parse->dts;
-
-          GST_LOG_OBJECT (h264parse,
-              "new buffering period; ts_trn_nb updated: %" GST_TIME_FORMAT,
-              GST_TIME_ARGS (h264parse->ts_trn_nb));
-          break;
-      }
+      gst_h264_parse_process_sei (h264parse, nalu);
       /* mark SEI pos */
       if (h264parse->sei_pos == -1) {
         if (h264parse->transform)