gcs_uri error on speech/grpc transcribe call #647

In which file did you encounter the issue?

speech/grpc$ python transcribe.py

Did you change the file? If so, how?

Describe the issue

Trying to transcribe a file that resides on an S3 bucket yields the following error (the file is accessible as you can do a wget on it and it works fine):

(env) vagrant@ubuntu16:~/speech/python/python-docs-samples/speech/grpc$ python transcribe.py https://s3-us-west-1.amazonaws.com/hackthon-audio/Happy-mac.raw
usage: transcribe.py [-h] [--encoding {LINEAR16,FLAC,MULAW,AMR,AMR_WB}]
[--sample_rate SAMPLE_RATE]
input_uri
transcribe.py: error: argument input_uri: invalid _gcs_uri value: 'https://s3-us-west-1.amazonaws.com/hackthon-audio/Happy-mac.raw'