From 7c72c89950fe3d82103e8b26c5082fb5bd83ac09 Mon Sep 17 00:00:00 2001
From: Logan G <logan@qtechofficial.com>
Date: Fri, 3 Jan 2025 18:29:08 -0700
Subject: [PATCH] Added ExtractAudio option

Let's you extract audio from combined video+audio media (most websites
supported by yt-dlp)
---
 download.go | 31 ++++++++++++++++++++++++++++++-
 ffmpeg.go   | 23 +++++++++++++++++++++++
 ytva.go     | 21 ++++++++++++---------
 3 files changed, 65 insertions(+), 10 deletions(-)

diff --git a/download.go b/download.go
index 11f0cb1..e828c76 100644
--- a/download.go
+++ b/download.go
@@ -78,7 +78,28 @@ func downloadVideo(url string, path string, group GroupConfig) (err error) {
     }
 
     /* AUDIO */
-    if group.AudioFormat != "" {
+    if group.ExtractFormat != "" {
+        log.Debugf("Extracting audio from \"%s\" with format \"%s\"", video.Info.ID, group.ExtractFormat)
+
+        audioDLResult, err := video.Download(context.Background(), group.ExtractFormat)
+        if err != nil {
+            return err
+        }
+
+        defer audioDLResult.Close()
+
+        file, err := os.OpenFile(tempPath+"-extract", os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0644)
+        if err != nil {
+            return err
+        }
+
+        defer file.Close()
+
+        io.Copy(file, audioDLResult)
+
+        audioDLResult.Close()
+        file.Close()
+    } else if group.AudioFormat != "" {
         log.Debugf("Downloading audio \"%s\" with format \"%s\"", video.Info.ID, group.AudioFormat)
 
         audioDLResult, err := video.Download(context.Background(), group.AudioFormat)
@@ -112,6 +133,14 @@ func downloadVideo(url string, path string, group GroupConfig) (err error) {
         if err := os.Remove(tempPath+"-audio"); err != nil {
             log.Warnf("Could not remove file \"%s\"", tempPath+"-audio")
         }
+    } else if group.ExtractFormat != "" {
+        if err := extractAudio(tempPath+"-extract", group.CFormat, path); err != nil {
+            log.Errorf("Could not extract audio from \"%s\" to \"%s\"", tempPath+"-extract", path)
+        }
+
+        if err := os.Remove(tempPath+"-extract"); err != nil {
+            log.Warnf("Could not remove file \"%s\"", tempPath+"-extract")
+        }
     } else if group.VideoFormat != "" {
         copyFile(tempPath+"-vid", path)
 
diff --git a/ffmpeg.go b/ffmpeg.go
index 13ecfbe..233bde1 100644
--- a/ffmpeg.go
+++ b/ffmpeg.go
@@ -29,3 +29,26 @@ func mergeStreams(path1 string, path2 string, format string, output string) (err
 
     return ffmpeg.Output(input, output, kwArgs).OverWriteOutput().ErrorToStdOut().Silent(silent).Run()
 }
+
+func extractAudio(path1 string, format string, output string) (err error) {
+    input := []*ffmpeg.Stream{ffmpeg.Input(path1)}
+
+    defaultArgs := ffmpeg.KwArgs{"map": "0:a", "c:a": "copy", "format": format}
+
+    var ffmpegLogLevel ffmpeg.KwArgs
+    var silent bool
+
+    if Flags.Verbose {
+        ffmpegLogLevel = ffmpeg.KwArgs{"v": "info"}
+        silent = false
+    } else if Flags.Quiet {
+        ffmpegLogLevel = ffmpeg.KwArgs{"v": "quiet"}
+        silent = true
+    } else {
+        ffmpegLogLevel = ffmpeg.KwArgs{"v": "error"}
+        silent = true
+    }
+
+    kwArgs := ffmpeg.MergeKwArgs([]ffmpeg.KwArgs{ffmpegLogLevel, defaultArgs})
+    return ffmpeg.Output(input, output, kwArgs).OverWriteOutput().ErrorToStdOut().Silent(silent).Run()
+}
diff --git a/ytva.go b/ytva.go
index faa7657..c3a231f 100644
--- a/ytva.go
+++ b/ytva.go
@@ -41,15 +41,18 @@ type _config struct {
 }
 
 type GroupConfig struct {
-    URL           []string
-    OutputDir       string
-    FileName        string
-    CFormat         string
-    VideoFormat     string
-    AudioFormat     string
-    NumVideos       uint
-    SizeLimit       float64
-    Filters         []struct {
+    URL                 []string
+    OutputDir           string
+    FileName            string
+    CFormat             string
+    ExtractFormat       string
+    VideoFormat         string
+    AudioFormat         string
+    DownloadSubtitles   bool // Currently useless
+    DownloadThumbnails  bool // Currently useless
+    NumVideos           uint
+    SizeLimit           float64
+    Filters             []struct {
         Name        string
         Input       string
         Pattern     string