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Be a bit smarter about aac/m4a files

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See #28
This commit is contained in:
Mikael Finstad 2017-03-19 17:25:25 +01:00
parent fa6c737bc4
commit 9d061ac5c3
1 changed files with 27 additions and 3 deletions
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30
src/ffmpeg.js
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@ -63,6 +63,29 @@ function cut(outputDir, filePath, format, cutFrom, cutTo) {
});
}
/**
* ffmpeg only supports encoding certain formats, and some of the detected input
* formats are not the same as the names used for encoding.
* Therefore we have to map between detected format and encode format
* See also ffmpeg -formats
*/
function mapFormat(requestedFormat) {
switch (requestedFormat) {
// These two cmds produce identical output, so we assume that encoding "ipod" means encoding m4a
// ffmpeg -i example.aac -c copy OutputFile2.m4a
// ffmpeg -i example.aac -c copy -f ipod OutputFile.m4a
// See also https://github.com/mifi/lossless-cut/issues/28
case 'm4a': return 'ipod';
case 'aac': return 'ipod';
default: return requestedFormat;
}
}
function determineOutputFormat(ffprobeFormats, ft) {
if (_.includes(ffprobeFormats, ft.ext)) return ft.ext;
return ffprobeFormats[0] || undefined;
}
function getFormat(filePath) {
return bluebird.try(() => {
console.log('getFormat', filePath);
@ -80,9 +103,10 @@ function getFormat(filePath) {
// ffprobe sometimes returns a list of formats, try to be a bit smarter about it.
return readChunk(filePath, 0, 4100)
.then((bytes) => {
const ft = fileType(bytes);
if (_.includes(formats, (ft || {}).ext)) return ft.ext;
return formats[0] || undefined;
const ft = fileType(bytes) || {};
console.log(`fileType detected format ${JSON.stringify(ft)}`);
const assumedFormat = determineOutputFormat(formats, ft);
return mapFormat(assumedFormat);
});
});
});