Add androidSdkless client to fix 403 errors on audio-only streams

[binSaed]

Audio-only streams return 403 while muxed streams work. Root cause: the android client includes androidSdkVersion which triggers YouTube's PO Token requirement.

Changes

• Added YoutubeApiClient.androidSdkless — Android client without androidSdkVersion field, based on yt-dlp's working implementation
• Changed default client from android to androidSdkless in StreamClient.getManifest()

Reference

From yt-dlp's _base.py:

# Doesn't require a PoToken for some reason
'android_sdkless': {
    'INNERTUBE_CONTEXT': {
        'client': {
            'clientName': 'ANDROID',
            'clientVersion': '20.10.38',
            # Note: no androidSdkVersion
            'userAgent': 'com.google.android.youtube/20.10.38 (Linux; U; Android 11) gzip',
            ...
        },
    },
    ...
}

The original android client is preserved for users who need it explicitly.

[Copilot]

Pull request overview

This PR adds a new androidSdkless YouTube API client to fix 403 errors that occur when streaming audio-only content. The root cause is that the existing android client includes an androidSdkVersion field which triggers YouTube's PO Token requirement.

Changes:

• Added YoutubeApiClient.androidSdkless client based on yt-dlp's working implementation that omits the androidSdkVersion field
• Changed the default client from android to androidSdkless in StreamClient.getManifest()
• Updated documentation for the existing android client to note PO Token requirements

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
lib/src/videos/youtube_api_client.dart	Adds new androidSdkless client constant and updates android client documentation
lib/src/videos/streams/stream_client.dart	Changes default client to androidSdkless for better compatibility

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[Copilot]

Consider adding a specific test case that validates the androidSdkless client works correctly with audio-only streams to prevent regressions of the 403 error issue this PR aims to fix. The test could use ytClients parameter to explicitly test both the old android client (expecting potential 403 errors) and the new androidSdkless client (expecting success).

[binSaed]

Issue

Code

final manifests = await _yt.videos.streams.getManifest( videoId);
final availableManifests = List<AudioStreamInfo>.of([]);

  await Future.wait([
    for (final manifest in manifests.audio)
      http.head(manifest.url).then((res) {
        print('$manifest : ${res.statusCode}');
        if (res.statusCode > 299 || res.statusCode < 200) return;
        availableManifests.add(manifest);
      }),
  ]);

Result

flutter: Muxed (18 | 640x360p30 | mp4) : 200 
flutter: Audio-only (599 | mp4 | null) : 403 
flutter: Audio-only (139 | mp4 | null) : 403 
flutter: Audio-only (140 | mp4 | null) : 403 
flutter: Audio-only (600 | webm | null) : 403 
flutter: Audio-only (249 | webm | null) : 403 
flutter: Audio-only (251 | webm | null) : 403

[lkvdy]

شكرااا