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Add support for aac format #208

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Add support for aac format #208

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a183a14
Skip unit test using /dev/null on Windows platforms.
Borewit Apr 28, 2019
3950249
Add/update support for MPEG-4/ADTS/AAC; mapped to aac extension.
Borewit Apr 28, 2019
2b4af51
#208 Fix MPEG/ADTS test, ADTS to audio/aac mime-type, skip ID3 tag-he…
Borewit Apr 30, 2019
16fa1cb
#208, #136 Mapped ADTS/MPEG-2/ACC to ext=.acc, mime=audio/aac.
Borewit Apr 30, 2019
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Binary file added fixture/fixture-adts-2.aac
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0 fixture/fixture-aac-adts.mp4 → fixture/fixture-adts.aac
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3 changes: 2 additions & 1 deletion index.d.ts
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Expand Up @@ -99,7 +99,8 @@ declare namespace fileType {
| 'lnk'
| 'alias'
| 'voc'
| 'ac3';
| 'ac3'
| 'aac';

interface FileTypeResult {
/**
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2 changes: 1 addition & 1 deletion index.js
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Expand Up @@ -443,7 +443,7 @@ const fileType = input => {
check([0xFF, 0xF0], {offset: start, mask: [0xFF, 0xFC]}) // MPEG 4 layer 0 using ADTS
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AAAAAAAA AAAABCCD

Letter Length (bits) Description
A 12 syncword 0xFFF, all bits must be 1
B 1 MPEG Version: 0 for MPEG-4, 1 for MPEG-2
C 2 Layer: always 0
D 1 protection absent, Warning, set to 1 if there is no CRC and 0 if there is CRC

2nd byte check should be 0b11110000(0xF0) with mask 0b11111110(0xFE) for aac then(and remaining options caught separately).

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also, shouldn't mpeg2 be caught too?

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There actually already is an ADTS/MPEG-2/ACC test file, originating from PR #136. Currently with .mp2 extension, it looks like to reverse engineered the extension based on the MPEG version.

Okay, lets assume this is ext. .acc mime audio/acc candidate as well.

) {
return {
ext: 'mp4',
ext: 'aac',
mime: 'audio/mpeg'
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Media type should probably be audio/aac, it's standardized.

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Media type should probably be audio/aac, it's standardized.

I think you are right: (ref)

"audio/aac" for sequences of ADTS frames, as specified in ISO/IEC 14496-3:2009

};
}
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1 change: 1 addition & 0 deletions readme.md
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Expand Up @@ -221,6 +221,7 @@ Type: [`stream.Readable`](https://nodejs.org/api/stream.html#stream_class_stream
- [`alias`](https://en.wikipedia.org/wiki/Alias_%28Mac_OS%29) - macOS Alias file
- [`voc`](https://wiki.multimedia.cx/index.php/Creative_Voice) - Creative Voice File
- [`ac3`](https://www.atsc.org/standard/a522012-digital-audio-compression-ac-3-e-ac-3-standard-12172012/) - ATSC A/52 Audio File
- [`aac`](https://en.wikipedia.org/wiki/Advanced_Audio_Coding) - Advanced Audio Coding

*SVG isn't included as it requires the whole file to be read, but you can get it [here](https://github.com/sindresorhus/is-svg).*

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27 changes: 17 additions & 10 deletions test.js
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Expand Up @@ -108,7 +108,9 @@ const types = [
'lnk',
'alias',
'voc',
'ac3'
'ac3',
'pcap',
'aac'
];

// Define an entry here only if the fixture has a different
Expand Down Expand Up @@ -153,8 +155,7 @@ const names = {
'fixture-isomv2',
'fixture-mp4v2',
'fixture-m4v',
'fixture-dash',
'fixture-aac-adts'
'fixture-dash'
],
tif: [
'fixture-big-endian',
Expand Down Expand Up @@ -199,6 +200,10 @@ const names = {
tar: [
'fixture',
'fixture-v7'
],
aac: [
'fixture-adts',
'fixture-adts-2'
]
};

Expand Down Expand Up @@ -257,13 +262,15 @@ for (const type of types) {
}
}

test('.stream() method - empty stream', async t => {
const emptyStream = fs.createReadStream('/dev/null');
await t.throwsAsync(
fileType.stream(emptyStream),
/Expected the `input` argument to be of type `Uint8Array` /
);
});
if (process.platform !== 'win32') {
test('.stream() method - empty stream', async t => {
const emptyStream = fs.createReadStream('/dev/null');
await t.throwsAsync(
fileType.stream(emptyStream),
/Expected the `input` argument to be of type `Uint8Array` /
);
});
}

test('fileType.minimumBytes', t => {
t.true(fileType.minimumBytes > 4000);
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