Merge pull request #401 from hyww/feat/webm-decrypt

try using shaka packager, which can handle WebM, to get KID
nilaoda · Jun 22, 2024 · 54a9eda · 54a9eda
2 parents a29c8b9 + 8fe77bd
commit 54a9eda
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diff --git a/src/N_m3u8DL-RE/DownloadManager/SimpleDownloadManager.cs b/src/N_m3u8DL-RE/DownloadManager/SimpleDownloadManager.cs
@@ -168,6 +168,10 @@ private async Task<bool> DownloadStreamAsync(StreamSpec streamSpec, ProgressTask
                 if (result != null && result.Success) 
                 {
                     currentKID = MP4DecryptUtil.ReadInit(result.ActualFilePath);
+                    // try shaka packager, which can handle WebM
+                    if (string.IsNullOrEmpty(currentKID) &&  DownloaderConfig.MyOptions.UseShakaPackager) {
+                        currentKID = MP4DecryptUtil.ReadInitShaka(result.ActualFilePath, mp4decrypt);
+                    }
                     //从文件读取KEY
                     await SearchKeyAsync(currentKID);
                     //实时解密
@@ -236,6 +240,10 @@ private async Task<bool> DownloadStreamAsync(StreamSpec streamSpec, ProgressTask
                     {
                         currentKID = MP4DecryptUtil.ReadInit(result.ActualFilePath);
                     }
+                    // try shaka packager, which can handle WebM
+                    if (string.IsNullOrEmpty(currentKID) &&  DownloaderConfig.MyOptions.UseShakaPackager) {
+                        currentKID = MP4DecryptUtil.ReadInitShaka(result.ActualFilePath, mp4decrypt);
+                    }
                     //从文件读取KEY
                     await SearchKeyAsync(currentKID);
                     //实时解密
@@ -577,6 +585,10 @@ await Parallel.ForEachAsync(segments, options, async (seg, _) =>
             if (mergeSuccess && totalCount >= 1 && string.IsNullOrEmpty(currentKID) && streamSpec.Playlist!.MediaParts.First().MediaSegments.First().EncryptInfo.Method != Common.Enum.EncryptMethod.NONE)
             {
                 currentKID = MP4DecryptUtil.ReadInit(output);
+                // try shaka packager, which can handle WebM
+                if (string.IsNullOrEmpty(currentKID) &&  DownloaderConfig.MyOptions.UseShakaPackager) {
+                    currentKID = MP4DecryptUtil.ReadInitShaka(output, mp4decrypt);
+                }
                 //从文件读取KEY
                 await SearchKeyAsync(currentKID);
             }

diff --git a/src/N_m3u8DL-RE/Util/MP4DecryptUtil.cs b/src/N_m3u8DL-RE/Util/MP4DecryptUtil.cs
@@ -3,6 +3,7 @@
 using N_m3u8DL_RE.Common.Resource;
 using N_m3u8DL_RE.Config;
 using System.Diagnostics;
+using System.Text.RegularExpressions;
 
 namespace N_m3u8DL_RE.Util
 {
@@ -144,5 +145,30 @@ await Process.Start(new ProcessStartInfo()
                 return ReadInit(header);
             }
         }
+
+        public static string? ReadInitShaka(string output, string bin)
+        {
+            Regex ShakaKeyIDRegex = new Regex("Key for key_id=([0-9a-f]+) was not found");
+
+            // TODO: handle the case that shaka packager actually decrypted (key ID == ZeroKid)
+            //       - stop process
+            //       - remove {output}.tmp.webm
+            var cmd = $"--quiet --enable_raw_key_decryption input=\"{output}\",stream=0,output=\"{output}.tmp.webm\" " +
+                    $"--keys key_id={ZeroKid}:key={ZeroKid}";
+
+            using var p = new Process();
+            p.StartInfo = new ProcessStartInfo()
+            {
+                FileName = bin,
+                Arguments = cmd,
+                RedirectStandardOutput = true,
+                RedirectStandardError = true,
+                UseShellExecute = false
+            };
+            p.Start();
+            var errorOutput = p.StandardError.ReadToEnd();
+            p.WaitForExit();
+            return ShakaKeyIDRegex.Match(errorOutput).Groups[1].Value;
+        }
     }
 }