Reducing the YouTube response time by 90%

Reducing the YouTube response time by 90%

In this blog post, we are going to cover how the audio from Youtube is being used in SUSI Smart Speaker and how we reduced the response time from ~40 seconds to ~4 seconds for an average music video length.

First Approach

Earlier, we were using MPV player’s inbuilt feature to fetch the YouTube music. However, MPV player was a bulky option and the music server had to be started every time before initiating a music video.

video_process = subprocess.Popen([‘mpv’, ‘–no-video’, ‘https://www.youtube.com/watch?v=’ + video_url[4:], ‘–really-quiet’]) # nosec #pylint-disable type: ignore requests.get(‘http://localhost:7070/song/’ + video_url) self.video_process = video_process stopAction.run() stopAction.detector.terminate()

Making it Efficient

To reduce the response time, we created a custom Music Server based on Flask,python-vlc and python-pafy which accepts requests from the main client and instructs the System to play the music with just 90% more efficiency.

app = Flask(__name__)

Instance = vlc.Instance(‘–no-video’)

player = Instance.media_player_new()

url = @app.route(‘/song’, methods=[‘GET’])

def youtube():

    vid = request.args.get(‘vid’)

    url = ‘https://www.youtube.com/watch?v=’ + vid

    video = pafy.new(url)
    streams = video.audiostreams 

    best = streams[3]

    playurl = best.url

    Media = Instance.media_new(playurl)

    Media.get_mrl()

    player.set_media(Media)

    player.play()

    display_message = {“song”:“started”}

    resp = jsonify(display_message)

    resp.status_code = 200

    return resp

However, shifting to this Server removed the ability to process multiple queries and hence we were unable to pause/play/stop the music until it completed the time duration. We wanted to retain the ability to have ‘play/pause/stop’ actions without implementing multiprocessing or multithreading as it would’ve required extensive testing to successfully implement them without creating deadlocks and would’ve been overkill for a simple feature.

Bringing Back the Lost Functionalities

The first Step we took was to remove the vlc-python module and implement a way to obtain an URL that we use in another asynchronous music player.

@app.route(‘/song’, methods=[‘GET’])
def youtube():

    vid = request.args.get(‘vid’)

    streams = video.audiostreams

    best = streams[3]

    playurl = best.url 

    display_message = {“song”: “started”, “url”: playurl}

    resp = jsonify(display_message)

    resp.status_code = 200

    return resp

The next issue was to actually find a way to run the Music Player asynchronously. We used the `subprocess. Popen` method and cvlc to play the songs asynchronously.

try:

    x = requests.get(‘http://localhost:7070/song?vid=’ + video_url[4:])

    data = x.json()

    url = data[‘url’]

    video_process = subprocess.Popen([‘cvlc’, ‘http’ + url[5:], ‘–no-video’])

    self.video_process = video_process

except Exception as e:

    logger.error(e);

And this is how we were able to increase the efficiency of the music player while maintaining the functionalities.

References

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