[fix] Readme typo

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alban 2020-09-29 15:55:11 +02:00
parent 3e630dc26e
commit 91c8fb3c9b

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@ -11,7 +11,7 @@ The idea is to share a single audio analysis to many Visual Jockey filters, in o
##### Each **word in bold** is a key which you can query the redis server for. Ex: ##### Each **word in bold** is a key which you can query the redis server for. Ex:
``` ```
$ redis-cli get spectrum_10 $ redis-cli get spectrum_1
"[2.21, 0.56, 0.51, 0.32, 0.27, 0.21, 0.18, 0.17, 0.18, 0.23]" "[2.21, 0.56, 0.51, 0.32, 0.27, 0.21, 0.18, 0.17, 0.18, 0.23]"
``` ```
@ -113,22 +113,22 @@ Redis_latency times are not considered here, but could be
Examples are given based on previous values for redis keys. Examples are given based on previous values for redis keys.
The calculation goes like #####The calculation goes like
0. How many second per beats? 0. **How many second per beats?**
* seconds_per_beat = 60 / bpm * seconds_per_beat = 60 / bpm
* ```60 / 126.05 =~ 0.4760``` * ```60 / 126.05 =~ 0.4760```
1. When did the capture start? 1. **When did the capture start?**
* total_delay = bpm_delay + pttl_delta * total_delay = bpm_delay + pttl_delta
* ```3197.49093056 + 2352 =~ 5549.5 ``` i.e. the capture started 5.5 seconds ago * ```3197.49093056 + 2352 =~ 5549.5 ``` i.e. the capture started 5.5 seconds ago
2. When was the last beat (in milliseconds)? 2. **When was the last beat (in milliseconds)?**
* last_beat_delay = bpm_delay - last_beat*1000 + pttl_delta * last_beat_delay = bpm_delay - last_beat*1000 + pttl_delta
* ```3197.49093056 - (2.48453515*1000) + 2352 =~ 3064.96 ``` i.e. the last beat was 3.1 seconds ago * ```3197.49093056 - (2.48453515*1000) + 2352 =~ 3064.96 ``` i.e. the last beat was 3.1 seconds ago
3. How many beats were there between the last beat and the redis `get bpm` query? 3. **How many beats were there between the last beat and the redis `get bpm` query?**
* count_past_beats = floor( (last_beat_delay / 1000) / seconds_per_beat) * count_past_beats = floor( (last_beat_delay / 1000) / seconds_per_beat)
* ```(3064.96/1000) / 0.4760 = 6.439``` e.g. there were at least 6 beats * ```(3064.96/1000) / 0.4760 = 6.439``` e.g. there were at least 6 beats
4. When are the next beats relative to the redis bpm key retrieval time (in milliseconds)? 4. **When are the next beats relative to the redis bpm key retrieval time (in milliseconds)?**
* next_beats = f(i){ i * seconds_per_beat * 1000 - last_beat_delay } where i >= count_past_beats * next_beats = f(i){ i * seconds_per_beat * 1000 - last_beat_delay } where i >= count_past_beats
* ```f(i){ i * 0.4760 * 1000 - 3064.96 } where i >= 4 * ```f(i){ i * 0.4760 * 1000 - 3064.96 }``` where i >= 4
* f(6) = 6 * 0.4760 * 1000 - 3064.96 = -208.9600 * f(6) = 6 * 0.4760 * 1000 - 3064.96 = -208.9600
* f(7) = 7 * 0.4760 * 1000 - 3064.96 = 267.0400 * f(7) = 7 * 0.4760 * 1000 - 3064.96 = 267.0400
* The next beat is in 267 milliseconds after the time we got the redis key * The next beat is in 267 milliseconds after the time we got the redis key