swift – iOS Radio App: Must extract and stream audio-only from HLS streams with video content material

I am growing an iOS radio app that performs numerous HLS streams. The problem is that some stations broadcast HLS streams containing each audio and video (instance: https://svs.itworkscdn.internet/smcwatarlive/smcwatar/chunks.m3u8), however I wish to:

Extract and play solely the audio observe
Assist AirPlay for audio-only streaming
Decrease information utilization by not downloading video content material
Technical Particulars:

iOS 17+
Swift 6
Utilizing AVFoundation for playback
Present implementation makes use of AVPlayer with AVPlayerItem
Present Code Construction:

class StreamPlayer: ObservableObject { @Revealed var isPlaying = false non-public var participant: AVPlayer? non-public var playerItem: AVPlayerItem?

func playStream(url: URL) {
    let asset = AVURLAsset(url: url)
    playerItem = AVPlayerItem(asset: asset)
    participant = AVPlayer(playerItem: playerItem)
    participant?.play()
}

Stream Evaluation: When analyzing the video stream utilizing FFmpeg:

CopyInput #0, hls, from 'https://svs.itworkscdn.internet/smcwatarlive/smcwatar/chunks.m3u8':
  Stream #0:0: Video: h264, yuv420p(television, bt709), 1920x1080 [SAR 1:1 DAR 16:9], 25 fps
  Stream #0:1: Audio: aac, 44100 Hz, stereo, fltp

Tried Options:

Utilizing MobileFFmpeg:

let command = [
    "-i", streamUrl,
    "-vn",
    "-acodec", "aac",
    "-ac", "2",
    "-ar", "44100",
    "-b:a", "128k",
    "-f", "mpegts",
    "udp://127.0.0.1:12345"
].joined(separator: " ")

ffmpegProcess = MobileFFmpeg.execute(command)

I

ssue: Whereas FFmpeg efficiently extracts audio, playback by way of AVPlayer does not work reliably.

Tried utilizing HLS output:

let command = [
    "-i", streamUrl,
    "-vn",
    "-acodec", "aac",
    "-ac", "2",
    "-ar", "44100",
    "-b:a", "128k",
    "-f", "hls",
    "-hls_time", "2",
    "-hls_list_size", "3",
    outputUrl.path
]

Challenge: Creates short-term recordsdata however faces synchronization points with dwell streams.

Testing URLs:

Audio+Video: https://svs.itworkscdn.internet/smcwatarlive/smcwatar/chunks.m3u8
Audio Solely: https://mbcfm-radio.mbc.internet/mbcfm-radio.m3u8

Necessities:

• Actual-time audio extraction from HLS stream
• Preserve dwell streaming capabilities
• Full AirPlay assist
• Minimal information utilization (keep away from downloading video content material)
• Deal with community interruptions gracefully

Questions:

• What’s essentially the most environment friendly approach to extract solely audio from an HLS stream in real-time?
• Is there a approach to inform AVPlayer to disregard video tracks utterly?
• Are there higher options to FFmpeg for this particular use case?
• What is the advisable method for dealing with AirPlay with modified streams?

Any steerage or various approaches could be significantly appreciated. Thanks!

What I Tried:

1. Direct AVPlayer Implementation:

• Used normal AVPlayer to play HLS stream
• Anticipated it to permit deciding on audio-only tracks
• Consequence: All the time downloads each video and audio, consuming pointless bandwidth

2. FFmpeg Audio Extraction:

let command = [
    "-i", "https://svs.itworkscdn.net/smcwatarlive/smcwatar/chunks.m3u8",
    "-vn",                    // Remove video
    "-acodec", "aac",        // Audio codec
    "-ac", "2",              // 2 channels
    "-ar", "44100",          // Sample rate
    "-b:a", "128k",          // Bitrate
    "-f", "mpegts",          // Output format
    "udp://127.0.0.1:12345"  // Local stream
]
ffmpegProcess = MobileFFmpeg.execute(command)

Anticipated: Clear audio stream that AVPlayer might play
Consequence: FFmpeg extracts audio however AVPlayer cannot play the UDP stream

3. HLS Segmented Strategy:

swiftCopylet command = [
    "-i", streamUrl,
    "-vn",
    "-acodec", "aac",
    "-f", "hls",
    "-hls_time", "2",
    "-hls_list_size", "3",
    outputUrl.path
]

Anticipated: Create native HLS playlist with audio-only segments
Consequence: Creates recordsdata however faces sync points with dwell stream

Anticipated Habits:

• Stream performs audio solely
• Minimal information utilization (no video obtain)
• Working AirPlay assist
• Actual-time playback with out delays

Precise Outcomes:

• Both downloads full video stream (wasteful)
• Or fails to play extracted audio
• AirPlay points with modified streams
• Sync issues with dwell content material