From 717b3e0122cd63397d4d7a19c34806de4e4f7d4c Mon Sep 17 00:00:00 2001
From: Anton Baklanov <anton@di.fm>
Date: Sat, 4 Feb 2017 22:54:19 +0200
Subject: [PATCH] ATDS: add AOT validation

MPEG 4 ADTS frame can not have AOT value greater than AAC_LTP.

For HE AAC (both v1 and v2) AOT should be set to AAC_LC. Clients are
supposed to use implicit SBR signaling to detect presence of SBR.

Ref:

https://github.com/FFmpeg/FFmpeg/blob/master/libavformat/adtsenc.c#L65
https://developer.apple.com/library/content/technotes/tn2236/_index.html
---
 format/aac/aac.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/format/aac/aac.go b/format/aac/aac.go
index 0ddce3b..5a65a87 100644
--- a/format/aac/aac.go
+++ b/format/aac/aac.go
@@ -30,6 +30,9 @@ func (self *Muxer) WriteHeader(streams []av.CodecData) (err error) {
 		return
 	}
 	self.config = streams[0].(aacparser.CodecData).Config
+	if self.config.ObjectType > aacparser.AOT_AAC_LTP {
+		err = fmt.Errorf("aac: AOT %d is not allowed in ADTS", self.config.ObjectType)
+	}
 	return
 }