From 1757d24e78ad81f03b22351e9cfb691b2a6cf235 Mon Sep 17 00:00:00 2001
From: John Calhoun <kcalhoun@vom.com>
Date: Sat, 4 Jul 2020 09:45:26 -0700
Subject: [PATCH] =?UTF-8?q?Per=20ISO=2014496-1=20=C2=A7=207.2.6.7.2,=20the?=
 =?UTF-8?q?=20semantics=20of=20decoder=20specific=20information=20depend?=
 =?UTF-8?q?=20on=20the=20value=20of=20DecoderConfigDescriptor.objectTypeIn?=
 =?UTF-8?q?dication.=20But=20for=20audio,=20mp4parse=20treats=20all=20deco?=
 =?UTF-8?q?der=20specific=20information=20as=20if=20it=20has=20the=20bit?=
 =?UTF-8?q?=20syntax=20defined=20for=20object=20type=20indication=200x40.?=
 =?UTF-8?q?=20This=20is=20not=20the=20case=20for=20object=20type=20indicat?=
 =?UTF-8?q?ions=200x69=20and=200x6B,=20which=20now=20have=20more=20recentl?=
 =?UTF-8?q?y=20defined=20decoder=20specific=20information=20with=20a=20dis?=
 =?UTF-8?q?tinct=20bit=20syntax,=20which=20Mozilla=20code=20can=20disregar?=
 =?UTF-8?q?d.=20This=20allows=20tracks=20carrying=20MP3=20audio=20to=20be?=
 =?UTF-8?q?=20parsed=20correctly=20when=20the=20new=20decoder=20specific?=
 =?UTF-8?q?=20info=20is=20present.?=
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Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 mp4parse/src/lib.rs | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/mp4parse/src/lib.rs b/mp4parse/src/lib.rs
index 9942288a..948eeffb 100644
--- a/mp4parse/src/lib.rs
+++ b/mp4parse/src/lib.rs
@@ -379,6 +379,7 @@ pub enum SampleEntry {
 #[allow(non_camel_case_types)]
 #[derive(Debug, Default)]
 pub struct ES_Descriptor {
+    pub object_profile: u8,
     pub audio_codec: CodecType,
     pub audio_object_type: Option<u16>,
     pub extended_audio_object_type: Option<u16>,
@@ -2452,7 +2453,16 @@ fn find_descriptor(data: &[u8], esds: &mut ES_Descriptor) -> Result<()> {
                 read_dc_descriptor(descriptor, esds)?;
             }
             DECODER_SPECIFIC_TAG => {
-                read_ds_descriptor(descriptor, esds)?;
+                match esds.object_profile {
+                    0x69 | 0x6B => {
+                        // Could parse these object types' decoder specific info
+                        // to discover the MPEG audio layer, etc., if needed.
+                        break;
+                    }
+                    _ => {
+                        read_ds_descriptor(descriptor, esds)?;
+                    }
+                };
             }
             _ => {
                 debug!("Unsupported descriptor, tag {}", tag);
@@ -2647,7 +2657,7 @@ fn read_surround_channel_count(bit_reader: &mut BitReader, channels: u8) -> Resu
 /// See ISO 14496-1:2010 § 7.2.6.6
 fn read_dc_descriptor(data: &[u8], esds: &mut ES_Descriptor) -> Result<()> {
     let des = &mut Cursor::new(data);
-    let object_profile = des.read_u8()?;
+    esds.object_profile = des.read_u8()?;
 
     // Skip uninteresting fields.
     skip(des, 12)?;
@@ -2656,9 +2666,9 @@ fn read_dc_descriptor(data: &[u8], esds: &mut ES_Descriptor) -> Result<()> {
         find_descriptor(&data[des.position().try_into()?..data.len()], esds)?;
     }
 
-    esds.audio_codec = match object_profile {
+    esds.audio_codec = match esds.object_profile {
         0x40 | 0x41 => CodecType::AAC,
-        0x6B => CodecType::MP3,
+        0x69 | 0x6B => CodecType::MP3,
         _ => CodecType::Unknown,
     };