From ecdaab175b098b4f86acab29d867bf36dfa3e3dd Mon Sep 17 00:00:00 2001
From: Saxon <saxon@ausocean.org>
Date: Wed, 11 Sep 2019 09:47:37 +0930
Subject: [PATCH] codec/h264/parse.go: skip over access unit delimiters when
 getting nalType

---
 codec/h264/h264dec/frame.go |  2 +-
 codec/h264/parse.go         | 39 +++++++++++++++++++++++--------------
 2 files changed, 25 insertions(+), 16 deletions(-)

diff --git a/codec/h264/h264dec/frame.go b/codec/h264/h264dec/frame.go
index ca85982b..1904a09d 100644
--- a/codec/h264/h264dec/frame.go
+++ b/codec/h264/h264dec/frame.go
@@ -11,7 +11,7 @@ const (
 	naluTypeSEI
 	NALTypeSPS
 	naluTypePPS
-	naluTypeAccessUnitDelimiter
+	NALTypeAccessUnitDelimiter
 	naluTypeEndOfSequence
 	naluTypeEndOfStream
 	naluTypeFillerData
diff --git a/codec/h264/parse.go b/codec/h264/parse.go
index 9465fb1c..accf68cf 100644
--- a/codec/h264/parse.go
+++ b/codec/h264/parse.go
@@ -26,34 +26,43 @@ LICENSE
 
 package h264
 
-import "errors"
+import (
+	"errors"
+
+	"bitbucket.org/ausocean/av/codec/h264/h264dec"
+)
 
 var errNotEnoughBytes = errors.New("not enough bytes to read")
 
 // NALType returns the NAL type of the given NAL unit bytes. The given NAL unit
 // may be in byte stream or packet format.
+// NB: access unit delimiters are skipped.
 func NALType(n []byte) (int, error) {
 	sc := frameScanner{buf: n}
-	b, ok := sc.readByte()
-	if !ok {
-		return 0, errNotEnoughBytes
-	}
-	for i := 1; b == 0x00 && i != 4; i++ {
-		b, ok = sc.readByte()
+	for {
+		b, ok := sc.readByte()
 		if !ok {
 			return 0, errNotEnoughBytes
 		}
-		if b != 0x01 || (i != 2 && i != 3) {
-			continue
-		}
+		for i := 1; b == 0x00 && i != 4; i++ {
+			b, ok = sc.readByte()
+			if !ok {
+				return 0, errNotEnoughBytes
+			}
+			if b != 0x01 || (i != 2 && i != 3) {
+				continue
+			}
 
-		b, ok = sc.readByte()
-		if !ok {
-			return 0, errNotEnoughBytes
+			b, ok = sc.readByte()
+			if !ok {
+				return 0, errNotEnoughBytes
+			}
+			nalType := int(b & 0x1f)
+			if nalType != h264dec.NALTypeAccessUnitDelimiter {
+				return nalType, nil
+			}
 		}
-		return int(b & 0x1f), nil
 	}
-	return int(b & 0x1f), nil
 }
 
 type frameScanner struct {