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MP4: Fix reading of sample rates for object types > 31

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Serial 2022-03-09 21:38:27 -05:00
parent 768fc8d875
commit d530fc3133
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1 changed files with 13 additions and 14 deletions
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27
src/mp4/properties.rs
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@ -302,24 +302,24 @@ where
// https://wiki.multimedia.cx/index.php?title=MPEG-4_Audio#Audio_Specific_Config
//
// 5 bits: object type (profile)
// 5 bits: object type
// if (object type == 31)
// 6 bits + 32: object type
// 4 bits: frequency index
// if (frequency index == 15)
// 24 bits: frequency
// 4 bits: channel configuration
let mut profile = stsd.read_u8()?;
let byte_a = stsd.read_u8()?;
let byte_b = stsd.read_u8()?;
let mut frequency_index = (profile << 5) | (byte_b >> 7);
let mut object_type = byte_a >> 3;
let mut frequency_index = (byte_a << 5) | (byte_b >> 7);
let mut extended_frequency_byte = None;
if (profile >> 3) == 31 {
profile = ((profile & 7) | (byte_b >> 5)) + 32;
let mut extended_object_type = false;
if object_type == 31 {
extended_object_type = true;
let frequency_ext = stsd.read_u8()?;
frequency_index = (byte_b & 0x0F) | (frequency_ext & 1);
extended_frequency_byte = Some(frequency_ext);
object_type = 32 + ((byte_a & 7) | (byte_b >> 5));
frequency_index = (byte_b >> 1) & 0x0F;
}
// TODO: Channels
@ -327,11 +327,10 @@ where
match frequency_index {
// 15 means the sample rate is stored in the next 24 bits
0x0F => {
if let Some(byte) = extended_frequency_byte {
let remaining_sample_rate =
u32::from(stsd.read_u16::<BigEndian>()?);
if extended_object_type {
let remaining_sample_rate = stsd.read_u24::<BigEndian>()?;
properties.sample_rate =
u32::from(byte >> 1) | remaining_sample_rate;
(remaining_sample_rate >> 1) | u32::from(byte_b & 1);
} else {
properties.sample_rate = stsd.read_uint::<BigEndian>(3)? as u32
}
@ -344,7 +343,7 @@ where
}
// https://en.wikipedia.org/wiki/MPEG-4_Part_3#MPEG-4_Audio_Object_Types
if profile == 36 {
if object_type == 36 {
let mut ident = [0; 5];
stsd.read_exact(&mut ident)?;