From 77988447553b909595e138efd8415e0cd649ea51 Mon Sep 17 00:00:00 2001
From: wukko <me@wukko.me>
Date: Mon, 28 Oct 2024 12:01:38 +0600
Subject: [PATCH] api/youtube: refactor, fix fallback, don't repeat same
 actions

fallback to h264 is now done if there's no required media, not only if adaptive formats list is empty.

best audio and best video are now picked only once.
---
 api/src/processing/services/youtube.js | 43 +++++++++++++-------------
 1 file changed, 22 insertions(+), 21 deletions(-)

diff --git a/api/src/processing/services/youtube.js b/api/src/processing/services/youtube.js
index b4583051..c045dce0 100644
--- a/api/src/processing/services/youtube.js
+++ b/api/src/processing/services/youtube.js
@@ -184,6 +184,7 @@ export default async function(o) {
     }
 
     let format = o.format || "h264";
+    let fallback = false;
 
     const filterByCodec = (formats) =>
         formats.filter(e =>
@@ -195,25 +196,32 @@ export default async function(o) {
 
     let adaptive_formats = filterByCodec(info.streaming_data.adaptive_formats);
 
-    if (adaptive_formats.length === 0 && ["vp9", "av1"].includes(format)) {
+    const checkBestVideo = (i) => (i.has_video && i.content_length);
+    const checkBestAudio = (i) => (i.has_audio && i.content_length && i.is_original);
+    const checkNoMedia = (video, audio) => (!video && !o.isAudioOnly) || (!audio && o.isAudioOnly);
+
+    const earlyBestVideo = adaptive_formats.find(i => checkBestVideo(i));
+    const earlyBestAudio = adaptive_formats.find(i => checkBestAudio(i));
+
+    // check if formats have all needed media and fall back to h264 if not
+    if (["vp9", "av1"].includes(format) && checkNoMedia(earlyBestVideo, earlyBestAudio)) {
+        fallback = true;
         format = "h264";
         adaptive_formats = filterByCodec(info.streaming_data.adaptive_formats);
     }
 
-    const bestVideo = adaptive_formats.find(i => i.has_video && i.content_length);
-    const hasAudio = adaptive_formats.find(i => i.has_audio && i.content_length);
+    const bestVideo = !fallback ? earlyBestVideo : adaptive_formats.find(i => checkBestVideo(i));
+    const bestAudio = !fallback ? earlyBestAudio : adaptive_formats.find(i => checkBestAudio(i));
 
-    if ((!bestVideo && !o.isAudioOnly) || (!hasAudio && o.isAudioOnly)) {
-        return { error: "fetch.empty" };
+    if (checkNoMedia(bestVideo, bestAudio)) {
+        return { error: "youtube.codec" };
     }
 
-    const checkBestAudio = (i) => (i.has_audio && !i.has_video);
-
-    let audio = adaptive_formats.find(i => checkBestAudio(i) && i.is_original);
+    let audio = bestAudio;
     let isDubbed;
 
     if (o.dubLang) {
-        let dubbedAudio = adaptive_formats.find(i =>
+        const dubbedAudio = adaptive_formats.find(i =>
             checkBestAudio(i) && i.language === o.dubLang && i.audio_track
         )
 
@@ -223,10 +231,6 @@ export default async function(o) {
         }
     }
 
-    if (!audio) {
-        audio = adaptive_formats.find(i => checkBestAudio(i));
-    }
-
     const fileMetadata = {
         title: cleanString(basicInfo.title.trim()),
         artist: cleanString(basicInfo.author.replace("- Topic", "").trim())
@@ -262,19 +266,16 @@ export default async function(o) {
     }
 
     const qual = (i) => {
-        if (!i.quality_label) {
-            return;
-        }
-
-        return i.quality_label.split('p', 2)[0].split('s', 2)[0]
+        if (!i.quality_label) return;
+        return i.quality_label.split('p', 2)[0].split('s', 2)[0];
     }
 
     const quality = o.quality === "max" ? "9000" : o.quality;
     const bestQuality = qual(bestVideo);
-    const matchingQuality = Number(quality) > Number(bestQuality) ? bestQuality : quality;
+    const useBestQuality = Number(quality) > Number(bestQuality);
 
-    const video = adaptive_formats.find(i =>
-        qual(i) === matchingQuality && i.has_video && !i.has_audio
+    const video = useBestQuality ? bestVideo : adaptive_formats.find(i =>
+        qual(i) === quality && checkBestVideo(i)
     );
 
     if (video && audio) {