144 lines
3.2 KiB
Markdown
144 lines
3.2 KiB
Markdown
# flac-metadata
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A FLAC metadata processor for Node.js, implemented as Transform stream.
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## Installation
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```npm install flac-metadata```
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## Usage Examples
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Some simple examples to get you started:
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#### Noop
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Does nothing, just pipes a source FLAC through the Processor into a target FLAC.
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```js
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var fs = require("fs");
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var flac = require("flac-metadata");
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var reader = fs.createReadStream("source.flac");
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var writer = fs.createWriteStream("target.flac");
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var processor = new flac.Processor();
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reader.pipe(processor).pipe(writer);
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```
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#### Trace Metadata
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Traces out the metadata from a FLAC file.
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```js
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var fs = require("fs");
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var flac = require("flac-metadata");
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var reader = fs.createReadStream("source.flac");
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var processor = new flac.Processor({ parseMetaDataBlocks: true });
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processor.on("postprocess", function(mdb) {
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console.log(mdb.toString());
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});
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reader.pipe(processor);
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```
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The output should be something like this:
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```
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[MetaDataBlockStreamInfo] type: 0, isLast: false
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minBlockSize: 4096
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maxBlockSize: 4096
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minFrameSize: 14
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maxFrameSize: 12389
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samples: 9750804
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sampleRate: 44100
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channels: 2
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bitsPerSample: 16
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duration: 3:41.107
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checksum: 1746dff27beb6d1875a88cfeed8a576b
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[MetaDataBlockVorbisComment] type: 4, isLast: false
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vendor: reference libFLAC 1.2.1 20070917
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comments:
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ALBUM: Close to the Glass
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ARTIST: The Notwist
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GENRE: Rock
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DATE: 2014
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TITLE: Signals
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[MetaDataBlockPicture] type: 6, isLast: true
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pictureType: 3
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mimeType: image/png
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description:
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width: 120
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height: 120
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bitsPerPixel: 32
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colors: 0
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pictureData: 391383
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```
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#### Strip All Metadata
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Pipes a source FLAC through the Processor into a target FLAC, removing all metadata.
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```js
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var fs = require("fs");
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var flac = require("flac-metadata");
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var reader = fs.createReadStream("source.flac");
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var writer = fs.createWriteStream("target.flac");
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var processor = new flac.Processor();
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processor.on("preprocess", function(mdb) {
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// STREAMINFO is always the first (and only mandatory) metadata block.
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if (mdb.type === flac.Processor.MDB_TYPE_STREAMINFO) {
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// When a metadata block's isLast flag is set to true in preprocess,
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// subsequent blocks are automatically discarded.
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mdb.isLast = true;
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}
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});
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reader.pipe(processor).pipe(writer);
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```
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#### Inject Metadata
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Injects a VORBIS_COMMENT block (and removes the existing one, if any).
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```js
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var fs = require("fs");
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var flac = require("flac-metadata");
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var reader = fs.createReadStream("source.flac");
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var writer = fs.createWriteStream("target.flac");
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var processor = new flac.Processor();
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var vendor = "reference libFLAC 1.2.1 20070917";
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var comments = [
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"ARTIST=Boyracer",
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"TITLE=I've Got It And It's Not Worth Having",
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"ALBUM=B Is For Boyracer",
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"TRACKNUMBER=A1",
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"DATE=1993",
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"DISCOGS=22379"
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];
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processor.on("preprocess", function(mdb) {
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// Remove existing VORBIS_COMMENT block, if any.
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if (mdb.type === flac.Processor.MDB_TYPE_VORBIS_COMMENT) {
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mdb.remove();
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}
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// Inject new VORBIS_COMMENT block.
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if (mdb.removed || mdb.isLast) {
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var mdbVorbis = flac.data.MetaDataBlockVorbisComment.create(mdb.isLast, vendor, comments);
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this.push(mdbVorbis.publish());
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}
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});
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reader.pipe(processor).pipe(writer);
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```
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## License
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MIT
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