[SenateISVP] not working

[porjo]

Attempting to record a live stream from the U.S. Senate results in an empty file e.g.

$ youtube-dl --verbose http://www.commerce.senate.gov/public/
[debug] System config: ['--prefer-free-formats']
[debug] User config: []
[debug] Command-line args: ['--verbose', 'http://www.commerce.senate.gov/public/']
[debug] Encodings: locale UTF-8, fs utf-8, out UTF-8, pref UTF-8
[debug] youtube-dl version 2015.11.27.1
[debug] Python version 3.4.3 - Linux-4.2.6-300.fc23.x86_64-x86_64-with-fedora-23-Twenty_Three
[debug] exe versions: ffmpeg 2.8.3, ffprobe 2.8.3, rtmpdump 2.4
[debug] Proxy map: {}
[generic] public: Requesting header
WARNING: Falling back on generic information extractor.
[generic] public: Downloading webpage
[generic] public: Extracting information
[SenateISVP] commerce120815: Downloading webpage
[SenateISVP] commerce120815: Downloading f4m manifest
[SenateISVP] commerce120815: Downloading m3u8 information
[debug] Invoking downloader on 'http://commerce1-f.akamaihd.net/z/commerce120815_1@80177/manifest.f4m?hdcore=3.1.0'
[f4m] Downloading f4m manifest
[f4m] Total fragments: 2
[download] Destination: Integrated Senate Video Player-commerce120815.flv
WARNING: Fragment 798 unavailable
WARNING: Fragment 799 unavailable
WARNING: Fragment 800 unavailable
WARNING: Fragment 801 unavailable
WARNING: Fragment 802 unavailable
WARNING: Fragment 803 unavailable
WARNING: Fragment 804 unavailable
WARNING: Fragment 805 unavailable
WARNING: Fragment 806 unavailable
WARNING: Fragment 807 unavailable
WARNING: Fragment 808 unavailable
WARNING: Fragment 809 unavailable
WARNING: Fragment 810 unavailable
WARNING: Fragment 811 unavailable
^C
ERROR: Interrupted by user

The resulting .part file appears to have an FLV header but no actual video. The same URL when viewed with Chrome browser shows a live video stream.