1256521 - SAPI speech rate conversion is not accurate

Status: RESOLVED FIXED

(Core :: Web Speech, defect)

Description

[Eitan Isaacson [:eeejay]]

The speech rate that is given is not correctly reflected in the output. For example, setting the uttance rate to 2, gives an increase of 1.43x.

Comment 1

[Eitan Isaacson [:eeejay]]

Attachment: Normalize speech rate in Windows.

MozReview-Commit-ID: EuQAqfoxwmo

Comment 2

[Eitan Isaacson [:eeejay]]

Benchmark with patch applied:

http://eeejay.github.io/webspeechdemos/rates.html?%5B%22urn%3Amoz-tts%3Asapi%3AMicrosoft%20Zira%20Desktop%20-%20English%20(United%20States)%3Fen-US%22%2C%22Microsoft%20Zira%20Desktop%20-%20English%20(United%20States)%22%2C%220.4086112493777999%22%2C%220.4584496816709483%22%2C%220.511432309513426%22%2C%220.5722950362520914%22%2C%220.7170058520394794%22%2C%220.8038582060321191%22%2C%221%22%2C%221.2490870359099209%22%2C%221.4075788751714677%22%2C%221.7665160318485045%22%2C%221.9591885441527446%22%2C%222.176876160169716%22%2C%222.387031113695842%22%5D

Comment 3

[Eitan Isaacson [:eeejay]]

Attachment: Normalize speech rate in Windows.

I removed the min/max clipping to allow the underlying engine to deal with rate values outside
the official "supported" range.

Comment 4

[Olli Pettay [:smaug][[e-mail]]]

Comment on attachment 8730840 [details] [diff] [review]
Normalize speech rate in Windows.

Am I missing something here, or does passing rate 0 really not work?
And since aRate isn't bounded in anyway, how is end results supposed to be [-10,10]

Comment 5

[Olli Pettay [:smaug][[e-mail]]]

With 0 case I mean that it is unclear what actually happens if 0 is passed as rate.

Comment 6

[Eitan Isaacson [:eeejay]]

(In reply to Olli Pettay [:smaug] from comment #4)
> Comment on attachment 8730840 [details] [diff] [review]
> Normalize speech rate in Windows.
> 
> Am I missing something here, or does passing rate 0 really not work?

Oops, totally bad stuff happens.

> And since aRate isn't bounded in anyway, how is end results supposed to be
> [-10,10]

According to the msdn docs, values above those bounds are allowed, but the engine does not need to support anything beyond.

But there is a good point here, SpeechSynthesisUtterance.rate should bind the rate to 0.1-10. From a test with Chrome, they do that. I'll open a new bug for that.

Comment 7

[Eitan Isaacson [:eeejay]]

Attachment: Normalize speech rate in Windows. r?smaug

MozReview-Commit-ID: EuQAqfoxwmo

Comment 8

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/5cb9d1e18724

Comment 9

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/5cb9d1e18724