Jim web wrote: > I think I now need to sort out switching to HLS for radio fetching rather > than RTMP! :-) > > I've been talking to someone, and my initial AIUI is... > > The 320k via HLS has been available for some months for most of the BBC > stations. The focus has since been on having this also via MPEG-DASH, plus > allowing the bitrate to be adaptable under the control of the > player/client.
Always great to hear your insights, Jim, but this doesn't seem correct. Let's take a look at yesterday's Afternoon Drama on Radio 4 as a test subject. If you happen to have an API key for Nitro, you can check which mediasets are available for the program: http://nitro.api.bbci.co.uk/nitro/api/programmes?api_key=<your_api_key>&mixin=versions_availability&pid=b06tvhnj No worries if you don't, but from the obtained list of mediasets, we can see that there are a number that support HLS streaming. Let's try the most common one: http://open.live.bbc.co.uk/mediaselector/5/select/version/2.0/vpid/b06tvhn1/format/xml/mediaset/apple-ipad-hls Which yields one selection at 128k: <media bitrate="128" encoding="aac" expires="2016-02-06T15:00:00Z" kind="audio" media_file_size="46827540" service="stream-uk-audio_streaming_aac_med" type="audio/mp4"> This remains the case despite which mediaset we ask for (iptv-all, journalism-http-tablet, apple-iphone4-hls, etc). They all return data for an HLS stream at 128k. On the other hand, if we query the mediaselectorr for the audio available via DASH: http://open.live.bbc.co.uk/mediaselector/5/select/version/2.0/vpid/b06tvhn1/format/xml/mediaset/pc/transferformat/dash <media bitrate="320" encoding="aac" expires="2016-02-06T15:00:00Z" kind="audio" service="stream-uk-audio_streaming_concrete_combined" type="audio/mp4"> We see that the audio is available at 320k. Finally, let's check what you would get if you used an iOS device to download the program (with DRM): http://open.live.bbc.co.uk/mediaselector/5/select/version/2.0/vpid/b06tvhn1/format/xml/mediaset/apple-ios-download-high <media bitrate="320" encoding="aac" expires="2016-02-06T15:00:00Z" kind="audio" media_file_size="1811" service="download-uk-audio_download_drm_aac_high" type="audio/mp4"> Of course, this is just one program of many, but I did try exactly the same procedure with a program from Radio 3, which are traditionally offered in higher bitrates, and saw the same results. But to sum up: - If you stream radio via HLS, you'll probably get 128k AAC. - If you stream the same program via DASH, you'll probably get 320k AAC. - If you download the DRM-protected version of the same program on your mobile device, you get 320k AAC. Of course, if the BBC say that HLS should offer 320k, then there's no reason to doubt their word. But in this instance, their own APIs report that it isn't available, so DASH is the clear winner. -- James Scholes http://twitter.com/JamesScholes _______________________________________________ get_iplayer mailing list [email protected] http://lists.infradead.org/mailman/listinfo/get_iplayer
