I didn't know that they'd done it in previous years, else I'd have recorded those as well – there are various concerts I'd have loved to have archived in 4.0, Vaughan Williams' Sea Symphony for a start.
The BBC stream it using using HTML5, MPEG-Dash, and the Media Source Extensions, giving a 320 kbit/s M/C M4A AAC stream. BBC say that Safari and Chrome on OS X should be able to decode this stream using Media Source Extensions, but I've only been able to get Chrome to work. Further, I've tried capturing the stream on the Mac, but nothing I have works. However, I've had success capturing it on Windows 8.1 using Chrome and Replay Media Catcher. I can't capture the raw AAC stream, despite having tried many different capture methods and programs. Instead, I record the 4-channel audio output from Chrome using Replay Media Catcher. It records to a 4-channel 16-bit LPCM WAV file. I then open it in Audacity to make minor edits before exporting it as a 6-channel LPCM WAV file, assigning the rear channels to channels 5 and 6 of the WAV file, leaving 3 and 4 empty.
As none of my hi-fi equipment can appear to play 6-channel LPCM WAV files (not that I've so far discovered anyway), I encode the WAV to 6-channel AAC at 512 kbit/s. My Mac is connected to its own hifi amp with a 7.1 surround setup in its room, so I can audition the files that way – they play back perfectly.
The audio broadcast over the web in 4.0 doesn't carry any of the Radio 3 presentations, and curiously doesn't carry any of the presenters' mics on-stage – you hear them from the 4.0 array picking up the amplified speech on the speakers in the hall. The mics go live pretty much at 7:30 (or 7pm, or 8pm/whatever) on the dot. Sometimes they're faded out for the interval, sometimes not.
Last night's balance engineer was a numpty. About 3min 30s before the Bruch began in the 2nd half, the levels on the rear channel shot up by 9db instantaneously – no fade up to it. It resulted in the rear channels being grossly dominant. At some point during the violinist's encore, they were faded down. I fixed it in Audacity, but the levels in Vaughan-Williams' "Toward the Unknown Region" were all over the shop. Loud passages were quickly faded down, as were the applause. I hope they have someone more competent on tonight.
Other than that, the experiment is going well, and I have everything captured from about Prom 5 onwards. The first 4 were a bit hit-and-miss as I experimented with various capture settings and methods.
Richard
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