Working with Streams and StreamQuery

The next section will explore the various options available for working with media streams, but before we can dive in, we need to review a new-ish streaming technique adopted by YouTube. It assumes that you have already created a YouTube object in your code called “yt”.

DASH vs Progressive Streams

Begin by running the following to list all streams:

>>> yt.streams
[<Stream: itag="18" mime_type="video/mp4" res="360p" fps="30fps" vcodec="avc1.42001E" acodec="mp4a.40.2" progressive="True" type="video">,
<Stream: itag="22" mime_type="video/mp4" res="720p" fps="30fps" vcodec="avc1.64001F" acodec="mp4a.40.2" progressive="True" type="video">,
<Stream: itag="137" mime_type="video/mp4" res="1080p" fps="30fps" vcodec="avc1.640028" progressive="False" type="video">,
...
<Stream: itag="250" mime_type="audio/webm" abr="70kbps" acodec="opus" progressive="False" type="audio">,
<Stream: itag="251" mime_type="audio/webm" abr="160kbps" acodec="opus" progressive="False" type="audio">]

You may notice that some streams listed have both a video codec and audio codec, while others have just video or just audio, this is a result of YouTube supporting a streaming technique called Dynamic Adaptive Streaming over HTTP (DASH).

In the context of pytube, the implications are for the highest quality streams; you now need to download both the audio and video tracks and then post-process them with software like FFmpeg to merge them.

The legacy streams that contain the audio and video in a single file (referred to as “progressive download”) are still available, but only for resolutions 720p and below.

Filtering Streams

Pytube has built-in functionality to filter the streams available in a YouTube object with the .filter() method. You can pass it a number of different keyword arguments, so let’s review some of the different options you’re most likely to use. For a complete list of available properties to filter on, you can view the API documentation here: pytube.StreamQuery.filter().

Filtering by streaming method

As mentioned before, progressive streams have the video and audio in a single file, but typically do not provide the highest quality media; meanwhile, adaptive streams split the video and audio tracks but can provide much higher quality. Pytube makes it easy to filter based on the type of stream that you’re interested.

For example, you can filter to only progressive streams with the following:

>>> yt.streams.filter(progressive=True)
[<Stream: itag="18" mime_type="video/mp4" res="360p" fps="30fps" vcodec="avc1.42001E" acodec="mp4a.40.2" progressive="True" type="video">,
<Stream: itag="22" mime_type="video/mp4" res="720p" fps="30fps" vcodec="avc1.64001F" acodec="mp4a.40.2" progressive="True" type="video">]

Conversely, if you only want to see the DASH streams (also referred to as “adaptive”) you can do:

>>> yt.streams.filter(adaptive=True)
[<Stream: itag="137" mime_type="video/mp4" res="1080p" fps="30fps" vcodec="avc1.640028" progressive="False" type="video">,
<Stream: itag="248" mime_type="video/webm" res="1080p" fps="30fps" vcodec="vp9" progressive="False" type="video">,
<Stream: itag="399" mime_type="video/mp4" res="None" fps="30fps" vcodec="av01.0.08M.08" progressive="False" type="video">,
...
<Stream: itag="250" mime_type="audio/webm" abr="70kbps" acodec="opus" progressive="False" type="audio">,
<Stream: itag="251" mime_type="audio/webm" abr="160kbps" acodec="opus" progressive="False" type="audio">]

Filtering for audio-only streams

To query the streams that contain only the audio track:

>>> yt.streams.filter(only_audio=True)
[<Stream: itag="140" mime_type="audio/mp4" abr="128kbps" acodec="mp4a.40.2" progressive="False" type="audio">,
<Stream: itag="249" mime_type="audio/webm" abr="50kbps" acodec="opus" progressive="False" type="audio">,
<Stream: itag="250" mime_type="audio/webm" abr="70kbps" acodec="opus" progressive="False" type="audio">,
<Stream: itag="251" mime_type="audio/webm" abr="160kbps" acodec="opus" progressive="False" type="audio">]

Filtering for MP4 streams

To query only streams in the MP4 format:

>>> yt.streams.filter(file_extension='mp4')
[<Stream: itag="18" mime_type="video/mp4" res="360p" fps="30fps" vcodec="avc1.42001E" acodec="mp4a.40.2" progressive="True" type="video">,
<Stream: itag="22" mime_type="video/mp4" res="720p" fps="30fps" vcodec="avc1.64001F" acodec="mp4a.40.2" progressive="True" type="video">,
<Stream: itag="137" mime_type="video/mp4" res="1080p" fps="30fps" vcodec="avc1.640028" progressive="False" type="video">,
...
<Stream: itag="394" mime_type="video/mp4" res="None" fps="30fps" vcodec="av01.0.00M.08" progressive="False" type="video">,
<Stream: itag="140" mime_type="audio/mp4" abr="128kbps" acodec="mp4a.40.2" progressive="False" type="audio">]