README
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Waveform peaks viewer
Renders a validator node's precomputed waveform peaks in
wavesurfer.js, beside wavesurfer decoding the same
audio itself. The point of the pair is to show that 750 bytes fetched from
/waveform/:cid describe the same track as several megabytes of mp3.
Requires a devnet node with OPENAUDIO_WAVEFORM_ENABLED=true — dev/env/openaudio-1.env
and openaudio-2.env set it.
make up
go run ./examples/waveform
Then open http://localhost:8777, pick an audio file, and press Upload to node.
The page uploads it, waits out the transcode and the analysis, and draws both panels
from that one file. To look at something already on the node, paste a 320 CID instead,
or pass one in the URL as ?cid=….
go run ./examples/waveform --node https://node2.oap.devnet --addr :9000
What you should see
The two panels will not be identical, and should not be. The node stores per-bucket RMS — average energy — while wavesurfer's default rendering draws per-bucket peak, the loudest single sample in the bucket. Peak rendering is spikier and reaches full height more often; RMS is flatter. Each is normalized to its own maximum, so absolute heights are not comparable either. The overall envelope is what should agree.
Why the audio is not proxied
Streaming audio from a node requires a signed request; the waveform does not. That asymmetry is the feature — a client can draw the waveform long before it is in a position to stream anything — so the reference panel decodes the file from local disk rather than pulling it back out of the node.
Documentation
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Overview ¶
Command waveform serves a small page that renders a validator node's precomputed waveform peaks in wavesurfer.
The waveform JSON is proxied through this process so the browser sees a single origin, which keeps the self-signed devnet certificate and any cross-origin rules out of the way.
Audio is deliberately not proxied. Serving it requires a signed request (/content and /tracks/cidstream both refuse an unsigned GET), whereas the waveform does not -- which is rather the point: a client can draw the waveform long before it is in a position to stream anything. To compare against ground truth, the page takes the source file from local disk.
go run ./examples/waveform go run ./examples/waveform --node https://node2.oap.devnet --addr :9000
Source Files