Add support for FLAC in sniffer and codecs package.

Author: codedread

codecs/codecs.js

@@ -51,9 +51,11 @@ export function getShortMIMEString(info) {
   if (!info) throw `Invalid ProbeInfo`;
   if (!info.streams || info.streams.length === 0) throw `No streams in ProbeInfo`;
 
-  // mp3 files are always considered audio/.
+  // mp3/flac files are always considered audio/ (even with mjpeg video streams).
   if (info.format.format_name === 'mp3') {
     return 'audio/mpeg';
+  } else if (info.format.format_name === 'flac') {
+    return 'audio/flac';
   }
 
   // Otherwise, any file with at least 1 video stream is considered video/.
@@ -106,8 +108,9 @@ export function getShortMIMEString(info) {
 export function getFullMIMEString(info) {
   /** A string like 'video/mp4' */
   let contentType = `${getShortMIMEString(info)}`;
-  // If MP3, just send back the type.
-  if (contentType === 'audio/mpeg') {
+  // If MP3/FLAC, just send back the type.
+  if (contentType === 'audio/mpeg'
+      || contentType === 'audio/flac') {
     return contentType;
   }
 
@@ -124,6 +127,7 @@ export function getFullMIMEString(info) {
             case 'opus': codecFrags.add('opus'); break;
             // I'm going off of what Chromium calls this one, with the dash.
             case 'ac3': codecFrags.add('ac-3'); break;
+            case 'flac': codecFrags.add('flac'); break;
             default:
               throw `Could not handle codec_name ${stream.codec_name}, ` +
                     `codec_tag_string ${stream.codec_tag_string} for file ${info.format.filename} yet. ` +

file/sniffer.js

@@ -31,6 +31,7 @@ const fileSignatures = {
   'image/webp': [[0x52, 0x49, 0x46, 0x46, '??', '??', '??', '??', 0x57, 0x45, 0x42, 0x50]],
   // Audio/Video formats.
   'application/ogg': [[0x4F, 0x67, 0x67, 0x53]],
+  'audio/flac': [[0x66, 0x4C, 0x61, 0x43]],
   'audio/mpeg': [[0xFF, 0xFB], [0xFF, 0xF3], [0xFF, 0xF2], [0x49, 0x44, 0x33]],
 };
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@codedread/bitjs",
-  "version": "1.0.8",
+  "version": "1.0.9",
   "description": "Binary Tools for JavaScript",
   "homepage": "https://github.com/codedread/bitjs",
   "author": "Jeff Schiller",

tests/codecs.spec.js

@@ -47,6 +47,13 @@ describe('codecs test suite', () => {
       })).equals('audio/mpeg');
     });
 
+    it('detects FLAC', () => {
+      expect(getShortMIMEString({
+        format: { format_name: 'flac' },
+        streams: [ { codec_type: 'audio'}, { codec_type: 'video' } ],
+      })).equals('audio/flac');
+    });
+
     it('detects AVI video', () => {
       expect(getShortMIMEString({
         format: { format_name: 'avi' },

tests/file-sniffer.spec.js

@@ -36,4 +36,5 @@ describe('bitjs.file.sniffer', () => {
   it('OGG', () => { sniffTest('application/ogg', [0x4F, 0x67, 0x67, 0x53]); });
   it('TAR_1', () => { sniffTest('application/x-tar', [0x75, 0x73, 0x74, 0x61, 0x72, 0x00, 0x30, 0x30]); });
   it('TAR_2', () => { sniffTest('application/x-tar', [0x75, 0x73, 0x74, 0x61, 0x72, 0x20, 0x20, 0x00]); });
+  it('FLAC', () => { sniffTest('audio/flac', [0x66, 0x4C, 0x61, 0x43]); });
 });