pythonogg

Getting the length of a ogg track from s3 without downloading the whole file

How do I get the play length of an ogg file without downloading the whole file? I know this is possible because both the HTML5 tag and VLC can show the entire play length immediately after loading the URL, without downloading the entire file.

Is there a header or something I can read. Maybe even the bitrate, which I can divide by the file size to get an approximate play length?

Solution

  • Unfortunately there does not appear to be a way to achieve this.

    Mozilla's Configuring servers for Ogg media is very instructive. Basically:

    1. Gecko uses the X-Content-Duration header - sent by the web server if it has it. This explains the HTML5 audio streaming example you raised. If missing, then
    2. Gecko estimates the length based on the sample-rate (in the header) and the size of the file from the Content-length HTTP header

    The sample rate is stored in the Identification Header - the first header packet. See the specification go to section "4.2 Header decode and decode setup"