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mp4a: Support DecoderSpecificDescriptor profiles > 30
Adds support for reading and writing AAC audio specific info when profile (object type) is larger than 30.
This commit is contained in:
parent
32674a6855
commit
0a3973b827
1 changed files with 60 additions and 5 deletions
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@ -507,14 +507,18 @@ impl Descriptor for DecoderSpecificDescriptor {
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}
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fn desc_size(&self) -> u32 {
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if self.profile < 31 {
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2
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} else {
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3
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}
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}
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}
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fn get_audio_object_type(byte_a: u8, byte_b: u8) -> u8 {
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let mut profile = byte_a >> 3;
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if profile == 31 {
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profile = 32 + ((byte_a & 7) | (byte_b >> 5));
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profile = 32 + ((byte_a & 7) << 3 | (byte_b >> 5));
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}
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profile
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@ -533,7 +537,7 @@ fn get_chan_conf<R: Read + Seek>(
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chan_conf = ((sample_rate >> 4) & 0x0F) as u8;
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} else if extended_profile {
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let byte_c = reader.read_u8()?;
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chan_conf = (byte_b & 1) | (byte_c & 0xE0);
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chan_conf = (byte_b & 1) << 3 | (byte_c >> 5);
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} else {
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chan_conf = (byte_b >> 3) & 0x0F;
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}
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@ -569,8 +573,15 @@ impl<W: Write> WriteDesc<&mut W> for DecoderSpecificDescriptor {
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let size = self.desc_size();
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write_desc(writer, Self::desc_tag(), size)?;
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writer.write_u8((self.profile << 3) + (self.freq_index >> 1))?;
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writer.write_u8((self.freq_index << 7) + (self.chan_conf << 3))?;
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if self.profile < 31 {
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writer.write_u8((self.profile << 3) | (self.freq_index >> 1))?;
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writer.write_u8((self.freq_index << 7) | (self.chan_conf << 3))?;
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} else {
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let profile_minus_32 = self.profile - 32;
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writer.write_u8(31u8 << 3 | profile_minus_32 >> 3)?;
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writer.write_u8(profile_minus_32 << 5 | self.freq_index << 1 | self.chan_conf >> 7)?;
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writer.write_u8((self.chan_conf & 7) << 5)?;
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}
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Ok(size)
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}
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@ -682,4 +693,48 @@ mod tests {
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let dst_box = Mp4aBox::read_box(&mut reader, header.size).unwrap();
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assert_eq!(src_box, dst_box);
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}
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#[test]
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fn test_decoder_specific_descriptor() {
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let test_dec_spec = |src_dec_spec: DecoderSpecificDescriptor| {
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let mut buf = Vec::new();
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let written = src_dec_spec.write_desc(&mut buf).unwrap();
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// expect two extra bytes for the tag and size fields
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assert_eq!(buf.len(), written as usize + 2);
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let mut reader = Cursor::new(&buf);
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let (tag, size) = read_desc(&mut reader).unwrap();
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assert_eq!(5, tag);
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assert_eq!(size, written);
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let dst_dec_spec = DecoderSpecificDescriptor::read_desc(&mut reader, written).unwrap();
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assert_eq!(src_dec_spec, dst_dec_spec);
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};
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test_dec_spec(DecoderSpecificDescriptor {
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profile: 2, // LC
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freq_index: 4, // 44100
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chan_conf: 2, // Stereo
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});
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test_dec_spec(DecoderSpecificDescriptor {
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profile: 5, // SpectralBandReplication (HEv1)
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freq_index: 3, // 48000
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chan_conf: 1, // Mono
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});
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test_dec_spec(DecoderSpecificDescriptor {
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profile: 29, // ParametricStereo (HEv2)
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freq_index: 2, // 64000
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chan_conf: 7, // SevenOne
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});
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test_dec_spec(DecoderSpecificDescriptor {
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profile: 34, // MpegLayer3
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freq_index: 4, // 44100
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chan_conf: 2, // Stereo
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});
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test_dec_spec(DecoderSpecificDescriptor {
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profile: 42, // UnifiedSpeechAudioCoding (xHE)
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freq_index: 11, // 8000
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chan_conf: 6, // FiveOne
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});
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}
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}
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