From 24312405b503314bf79066f95c437b152b28824e Mon Sep 17 00:00:00 2001
From: Jeff Schiller <codedread@gmail.com>
Date: Sun, 5 Feb 2023 21:44:00 -0800
Subject: [PATCH] Improve handling of fLaC

---
 codecs/codecs.js     | 15 ++++++++-------
 tests/codecs.spec.js | 39 ++++++++++++++++++++++++++++++++++++++-
 2 files changed, 46 insertions(+), 8 deletions(-)

diff --git a/codecs/codecs.js b/codecs/codecs.js
index 997f468..7354497 100644
--- a/codecs/codecs.js
+++ b/codecs/codecs.js
@@ -127,9 +127,10 @@ 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;
+            // It seems to be "fLaC".
+            case 'flac': codecFrags.add(stream.codec_tag_string); break;
             default:
-              throw `Could not handle codec_name ${stream.codec_name}, ` +
+              throw `Could not handle audio codec_name ${stream.codec_name}, ` +
                     `codec_tag_string ${stream.codec_tag_string} for file ${info.format.filename} yet. ` +
                     `Please file a bug https://github.com/codedread/bitjs/issues/new`;
           }
@@ -141,16 +142,16 @@ export function getFullMIMEString(info) {
         case 'avc1': codecFrags.add(getAVC1CodecString(stream)); break;
         case 'vp09': codecFrags.add(getVP09CodecString(stream)); break;
         // We don't handle these as video streams with codecs, so skip them.
-        case 'png':
-        case 'mjpeg':
-          continue;
+        case 'png': continue;
         default:
           switch (stream.codec_name) {
             case 'h264': codecFrags.add(getAVC1CodecString(stream)); break;
-            case 'vp9': codecFrags.add(getVP09CodecString(stream)); break;
             case 'mpeg2video': codecFrags.add('mpeg2video'); break;
+            // Skip mjpeg as a video stream for the codecs string.
+            case 'mjpeg': break;
+            case 'vp9': codecFrags.add(getVP09CodecString(stream)); break;
             default:
-              throw `Could not handle codec_name ${stream.codec_name}, ` +
+              throw `Could not handle video codec_name ${stream.codec_name}, ` +
                     `codec_tag_string ${stream.codec_tag_string} for file ${info.format.filename} yet. ` +
                     `Please file a bug https://github.com/codedread/bitjs/issues/new`;
 
diff --git a/tests/codecs.spec.js b/tests/codecs.spec.js
index 0e76354..efe9fb8 100644
--- a/tests/codecs.spec.js
+++ b/tests/codecs.spec.js
@@ -49,7 +49,7 @@ describe('codecs test suite', () => {
 
     it('detects FLAC', () => {
       expect(getShortMIMEString({
-        format: { format_name: 'flac' },
+        format: { format_name: 'flac', format_tag_string: 'fLaC' },
         streams: [ { codec_type: 'audio'}, { codec_type: 'video' } ],
       })).equals('audio/flac');
     });
@@ -341,6 +341,43 @@ describe('codecs test suite', () => {
     });
   });
 
+  describe('MP4 / FLAC', () => {
+    /** @type {ProbeInfo} */
+    let info;
+
+    beforeEach(() => {
+      info = {
+        format: { format_name: 'mov,mp4,m4a,3gp,3g2,mj2' },
+        streams: [{
+          codec_type: 'audio',
+          codec_tag_string: 'mp4a',
+        }],
+      };
+    });
+
+    it('audio/mp4 handles fLaC', () => {
+      info.streams[0].codec_tag_string = 'fLaC';
+      info.streams[0].codec_name = 'flac';
+      expect(getFullMIMEString(info))
+          .to.be.a('string')
+          .and.equals('audio/mp4; codecs="fLaC"');
+    });
+
+    it('video/mp4 handles fLaC', () => {
+      const vInfo = structuredClone(info);
+      vInfo.streams[0].codec_tag_string = 'fLaC';
+      vInfo.streams[0].codec_name = 'flac';
+      vInfo.streams.push({
+        codec_type: 'video',
+        codec_name: 'mjpeg',
+      });
+      expect(getFullMIMEString(vInfo))
+          .to.be.a('string')
+          .and.equals('video/mp4; codecs="fLaC"');
+      
+    });
+  });
+
   describe('Vorbis', () => {
     /** @type {ProbeInfo} */
     let info;