> On Aug 5, 2015, at 12:39 AM, Matthew Pease <[email protected]> wrote: > > The more detailed version is that I'd like to provide a Tivo style ability > to seek in the recent history of a stream. I want to display the entire > history of the stream as graph of the levels. So that the user can see > where there is activity within the stream. The app would allow them to > quickly jump to some point in the history.
Ah, you want a waveform view. I’ve implemented this by rendering to a low-resolution PCM stream (e.g. 8khz 8-bit mono) then running some simple processing on the stream to capture the maximum absolute value in every bin of x ms, where the value of x depends on the resolution you want for your display. (The trickiest thing to work out was the conversion from raw amplitude to a volume level; I went with the cube root.) —Jens
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