README
¶
Audio Stream
This exercise is about streaming. The private method sendStreamToGCP sends an audio stream
of bytes, read from a test audio .wav file in public/ directory. The readStreamFromGCP
it then receives the speech-to-text stream and prints it. To run this please
ensure that you have set GOOGLE_APPLICATION_CREDENTIALS with appropriate permissions
for your GCP Project.
The go routines run in parallel:
- sendStreamToGCP: audio file => Reader() stream => StreamingRecognizeClient Send()
- readStreamFromGCP: StreamingRecognizeClient Recv() => stream Writer() => os.Stdout
The API limits are specified in Quotas & limits.
There is no limit on this streaming version. Below is the transcription of I Have a Dream, Martin Luther King Jr.
speech by this API. The speech audio is 16 minutes long (at 22K bit rate).
Mac Audio
On a Mac:
- You can create a sample .wav file using
ffmpegpre-installed program. - Or you can stream audio to UDP port and forward it using Go routing to recognizer.
Audio Samples on Mac
As example epilogue of A Pale Blue Dot recorded
in public/paleBlueDot.wav:
There is perhaps no better demonstration of the folly of human
conceits than this distant image of our tiny world. To me, it underscores our
responsibility to deal more kindly with one another, and to preserve and cherish
the pale blue dot, the only home we've ever known.
The Google ML command line shows the reference output:
gcloud ml speech recognize ../../public/paleBlueDot.wav --language-code=en_US
Output:
{
"results": [
{
"alternatives": [
{
"confidence": 0.9397845,
"transcript": "there is perhaps no better demonstration of the Folly of human conceit than this image of a world to me and of course a responsibility to deal more kindly with one another and to preserve and cherish the pale blue dot"
}
]
}
]
}
You can check out yourself what stream client returned.
Handy Mac Shell Commands
You can use ffmpeg Mac command line program to record a .wav file or stream PCM to a
UDP port. Some examples are:
# List livecaption devices, Mac
ffmpeg -f avfoundation -list_devices true -i ""
# Record 20 seconds of livecaption from the built in microphone and save it in playBlueDot.mp3
ffmpeg -f avfoundation -i ":1" -t 20 ../../public/playBlueDot.wav
# Stream s16le to a UDP port 9999, and send that livecaption to GCP
ffmpeg -f avfoundation -i ":1" -acodec pcm_s16le -ar 48000 -f s16le udp://localhost:9999
ffmpeg -formats | grep PCM # see pcl formats
nc -u -l localhost 9999 # Starts a UDP server, and listen to the port
nc -u localhost 9999 # stats a client
# Meta data
mdls chapter1/audio/playBlueDot.wav
# Test playback
afplay chapter1/audio/playBlueDot.wav
ffmpeg -i inputFilename.m4a OutputFilename.wav
The same command can be used to recording Video files:
# Record from video device 0 and livecaption device 0:
ffmpeg -r 30 -f avfoundation -i "0:1" ../../public/paleBlueDot.mp4
ffmpeg -f avfoundation -framerate 30 -video_size 640x480 -i "0:1" ../../public/paleBlueDot.mp4
Formats flag in the command are:
ffmpeg flags:
-f = "force format". In this case we're forcing the use of AVFoundation
-i = input source. Typically it's a file, but you can use devices.
"0:1" = Record both audio and video from FaceTime camera and built-in mic
"0" = Record just video from FaceTime camera
":1" = Record just audio from built-in mic
-t = time in seconds. If you want it to run indefinitely until you stop it (ControlC)
Material:
You may find following links handy if you like to check more audio related stuff in Golang.
- FFMPEG a complete, cross-platform solution to record, convert and stream audio and video.
- Creating Multiple Outputs
- How to stream audio using FFMPEG?
- PortAudioAPI Overview
- Golang Package PortAudio
- How to build an audio streaming server in Go
- Live Caption Sample Code
- Transcribing audio from streaming input
- Endless streaming tutorials
- I Have a Dream, Martin Luther King Jr.
MLK Speech Transcribed
Words transcribed: 529 v/s actual words in speech 881.
I say to you today my friend
so even though we Face the difficulties of today and tomorrow
I still have a dream
it is a dream deeply rooted in the American dream
I have a dream
one day
this nation will rise up
live out the true meaning of its trees
we hold these truths to be self-evident that all men are created equal
I have a dream
that one day on the Red Hills of Georgia
sons of former slaves and the sons of former slave owners
will baby be able to sit down together at the table of Brotherhood I have a dream
the one thing
even the state of Mississippi a state sweltering with the keto Zone Injustice
sweltering with the heat of Oppression
be transformed into an oasis of freedom and Justice I have a trees
my four little children
one day live in a nation where they will not be judged by the color of their skin but by the content of a character I have a dream today
I have a dream that one day
in Alabama with its vicious racists
what's its Governor having his lips dripping with the words of interposition and nullification one day right there in Alabama little black boys and black girls little join hands with little white balls and white girls as sisters and brothers I have a dream today
I have a dream that one day I shall be exalted never healed in Mountain shall be made Low Places would be made friends and the Crooked places will be made at All Flesh shall see it together and I hope this is a piece that I go back to the Southwest River space we will be able to shoot out of the Mountain of Despair a stone of hope we will be able to transform the jangling call Javon nation into a beautiful Symphony of Brotherhood with this face we will be able to work together to pray together to struggle together to go to jail for Freedom together knowing that we will be free one day
this will be the day
this will be the day when all of God's children
be able to sing with new meaning my country tears would be
sweet land of liberty of Beyonce the Pilgrim's Pride from every Mountainside Let Freedom Ring Americans to be a great nation this must be come true and so Let Freedom Ring
from the mighty mountains of New York
Let Freedom Ring from the highwomen alligators of Pennsylvania Let Freedom Ring from the smoke
Let Freedom Ring from the probation. California but not only that
Let Freedom Ring from Stone Mountain of Georgia
Let Freedom Ring from Lookout Mountain of Tennessee and Mississippi State play tomorrow in Japanese
turn wheel of freedom
when we let it ring from every finish whatever Hamlet from every state and their Parsippany
we will be able to speed up that they put on Jews and Gentiles Protestants and Catholics will be able to tell her I'm sending the words of the old Negro spiritual free at last free at last thank God Almighty we are free
Documentation
¶
Overview ¶
Package livecaption implements Google speech-to-text API. It inputs audio from RTP stream and associates a connection with GCP and displays the output on terminal. Red color text is not final and Green color text is final output of speech recognizer.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func InitCli ¶
func InitCli()
InitCli for command: the-gpl stt # Convert Speech on port 9999 to text
eg: the-gpl stt -port=9999
func StreamAudioFile ¶
StreamAudioFile streams a livecaption file to Google Speech to text recognizer
func StreamRTPPort ¶
Types ¶
type CLI ¶
type CLI struct {
// contains filtered or unexported fields
}
CLI wrapper for *flag.FlagSet. Implements serve.CmdHandlers CLI interface.
func (CLI) DisplayHelp ¶
func (a CLI) DisplayHelp()
DisplayHelp prints help on command line for the live-caption module
type LineColor ¶
type LineColor string
LineColor defined a colors for a line, see Terminal output in Go.
Source Files