From 19e12b5e282e661a9a17a6bfbb87c565faf2bc6e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=81lvaro=20Velad=20Galv=C3=A1n?= <alvaro.velad@mirada.tv>
Date: Wed, 20 Apr 2022 23:23:54 +0200
Subject: [PATCH] feat(hls): make a head request if hls subtitles have no
 extension (#4140)

Closes https://github.com/shaka-project/shaka-player/issues/4135
Closes https://github.com/shaka-project/shaka-player/issues/1959
---
 lib/hls/hls_parser.js       | 10 ++++--
 test/hls/hls_parser_unit.js | 63 +++++++++++++++++++++++++++++++++++++
 2 files changed, 70 insertions(+), 3 deletions(-)

diff --git a/lib/hls/hls_parser.js b/lib/hls/hls_parser.js
index 97934283f2..5817a1d06d 100644
--- a/lib/hls/hls_parser.js
+++ b/lib/hls/hls_parser.js
@@ -2252,11 +2252,10 @@ shaka.hls.HlsParser = class {
 
     if (contentType == ContentType.TEXT) {
       // The extension map didn't work.
-      if (!codecs || codecs == 'vtt' || codecs == 'wvtt') {
+      if (codecs == 'vtt' || codecs == 'wvtt') {
         // If codecs is 'vtt', it's WebVTT.
-        // If there was no codecs string, assume HLS text streams are WebVTT.
         return 'text/vtt';
-      } else {
+      } else if (codecs && codecs !== '') {
         // Otherwise, assume MP4-embedded text, since text-based formats tend
         // not to have a codecs string at all.
         return 'application/mp4';
@@ -2281,6 +2280,11 @@ shaka.hls.HlsParser = class {
     const contentMimeType = response.headers['content-type'];
 
     if (!contentMimeType) {
+      if (contentType == ContentType.TEXT) {
+        // If there was no codecs string and no content-type, assume HLS text
+        // streams are WebVTT.
+        return 'text/vtt';
+      }
       // If the HLS content is lacking in both MIME type metadata and
       // segment file extensions, we fall back to assuming it's MP4.
       const fallbackMimeType = map['mp4'];
diff --git a/test/hls/hls_parser_unit.js b/test/hls/hls_parser_unit.js
index 1bc5e82595..dad19f5188 100644
--- a/test/hls/hls_parser_unit.js
+++ b/test/hls/hls_parser_unit.js
@@ -1138,6 +1138,69 @@ describe('HlsParser', () => {
     expect(actual).toEqual(manifest);
   });
 
+  it('gets mime type of SUBTITLES from header request', async () => {
+    const master = [
+      '#EXTM3U\n',
+      '#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="aud1",LANGUAGE="eng",',
+      'URI="audio"\n',
+      '#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="sub1",LANGUAGE="eng",',
+      'URI="text"\n',
+      '#EXT-X-STREAM-INF:BANDWIDTH=200,CODECS="avc1,mp4a",',
+      'RESOLUTION=960x540,FRAME-RATE=60,AUDIO="aud1",SUBTITLES="sub1"\n',
+      'video\n',
+    ].join('');
+
+    const media = [
+      '#EXTM3U\n',
+      '#EXT-X-PLAYLIST-TYPE:VOD\n',
+      '#EXT-X-MAP:URI="init.mp4",BYTERANGE="616@0"\n',
+      '#EXTINF:5,\n',
+      '#EXT-X-BYTERANGE:121090@616\n',
+      'main.mp4',
+    ].join('');
+
+    const textMedia = [
+      '#EXTM3U\n',
+      '#EXT-X-PLAYLIST-TYPE:VOD\n',
+      '#EXTINF:5,\n',
+      '#EXT-X-BYTERANGE:121090@616\n',
+      'main.subs',
+    ].join('');
+
+    const manifest = shaka.test.ManifestGenerator.generate((manifest) => {
+      manifest.anyTimeline();
+      manifest.addPartialVariant((variant) => {
+        variant.addPartialStream(ContentType.VIDEO, (stream) => {
+          stream.mime('video/mp4', 'avc1');
+        });
+        variant.addPartialStream(ContentType.AUDIO, (stream) => {
+          stream.mime('audio/mp4', 'mp4a');
+        });
+      });
+      manifest.addPartialTextStream((stream) => {
+        stream.language = 'en';
+        stream.kind = TextStreamKind.SUBTITLE;
+        stream.mime('application/mp4', '');
+      });
+      manifest.sequenceMode = true;
+    });
+
+    fakeNetEngine
+        .setResponseText('test:/master', master)
+        .setResponseText('test:/audio', media)
+        .setResponseText('test:/video', media)
+        .setResponseText('test:/text', textMedia)
+        .setResponseText('test:/main.subs', vttText)
+        .setHeaders('test:/main.subs', {
+          'content-type': 'application/mp4; foo=bar',
+        })
+        .setResponseValue('test:/init.mp4', initSegmentData)
+        .setResponseValue('test:/main.mp4', segmentData);
+
+    const actual = await parser.start('test:/master', playerInterface);
+    expect(actual).toEqual(manifest);
+  });
+
   it('parses manifest with FORCED SUBTITLES', async () => {
     const master = [
       '#EXTM3U\n',