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I'm getting following response when using putMedia api using python.

Response code: 200

{"Output":{"__type":"com.amazon.coral.service#SerializationException","Message":null},"Version":"1.0"}

I have saved video frames locally and trying to post first frame on the amazon video stream. I have signed using Signing AWS Requests with Signature Version 4 instructions.

Below is my code -

import sys, os, base64, datetime, hashlib, hmac, time 
import requests # pip install requests

# ************* REQUEST VALUES *************
method = 'POST'
service = 'kinesisvideo'
host = 's-1110bf70.kinesisvideo.us-west-2.amazonaws.com'
region = 'us-west-2'
endpoint = 'https://s-1110bf70.kinesisvideo.us-west-2.amazonaws.com'
# POST requests use a content type header. For DynamoDB,
# the content is JSON.
content_type = 'application/json'
start_tmstp = repr(time.time())
localfile = 'mkv-0.jpg';
with open(localfile,'rb') as image:
      request_parameters = image.read()

# Key derivation functions. See:
# http://docs.aws.amazon.com/general/latest/gr/signature-v4-examples.html#signature-v4-examples-python
def sign(key, msg):
    return hmac.new(key, msg.encode("utf-8"), hashlib.sha256).digest()

def getSignatureKey(key, date_stamp, regionName, serviceName):
    kDate = sign(('AWS4' + key).encode('utf-8'), date_stamp)
    kRegion = sign(kDate, regionName)
    kService = sign(kRegion, serviceName)
    kSigning = sign(kService, 'aws4_request')
    return kSigning

# Read AWS access key from env. variables or configuration file. Best practice is NOT
# to embed credentials in code.
access_key = '***********'
secret_key = '*************'
if access_key is None or secret_key is None:
    print('No access key is available.')
    sys.exit()

# Create a date for headers and the credential string
t = datetime.datetime.utcnow()
amz_date = t.strftime('%Y%m%dT%H%M%SZ')
date_stamp = t.strftime('%Y%m%d') # Date w/o time, used in credential scope


# ************* TASK 1: CREATE A CANONICAL REQUEST *************
# http://docs.aws.amazon.com/general/latest/gr/sigv4-create-canonical-request.html

# Step 1 is to define the verb (GET, POST, etc.)--already done.

# Step 2: Create canonical URI--the part of the URI from domain to query 
# string (use '/' if no path)
canonical_uri = '/putMedia'

## Step 3: Create the canonical query string. In this example, request
# parameters are passed in the body of the request and the query string
# is blank.
canonical_querystring = ''

# Step 4: Create the canonical headers. Header names must be trimmed
# and lowercase, and sorted in code point order from low to high.
# Note that there is a trailing \n.
canonical_headers = 'content-type:' + content_type + '\n' + 'host:' + host + '\n' + 'x-amz-content-sha256:' + 'UNSIGNED-PAYLOAD' + '\n' + 'x-amz-date:' + amz_date + '\n' + 'x-amz-target:' + amz_target + '\n' + 'x-amzn-fragment-timecode-type:' + 'ABSOLUTE' + '\n' + 'x-amzn-producer-start-timestamp:' + start_tmstp + '\n' + 'x-amzn-stream-name:' + 'ExampleStream' + '\n'

# Step 5: Create the list of signed headers. This lists the headers
# in the canonical_headers list, delimited with ";" and in alpha order.
# Note: The request can include any headers; canonical_headers and
# signed_headers include those that you want to be included in the
# hash of the request. "Host" and "x-amz-date" are always required.
# For DynamoDB, content-type and x-amz-target are also required.
signed_headers = 'content-type;host;x-amz-content-sha256;x-amz-date;x-amz-target;x-amzn-fragment-timecode-type;x-amzn-producer-start-timestamp;x-amzn-stream-name'

# Step 6: Create payload hash. In this example, the payload (body of
# the request) contains the request parameters.

# Step 7: Combine elements to create canonical request
canonical_request = method + '\n' + canonical_uri + '\n' + canonical_querystring + '\n' + canonical_headers + '\n' + signed_headers


# ************* TASK 2: CREATE THE STRING TO SIGN*************
# Match the algorithm to the hashing algorithm you use, either SHA-1 or
# SHA-256 (recommended)
algorithm = 'AWS4-HMAC-SHA256'
credential_scope = date_stamp + '/' + region + '/' + service + '/' + 'aws4_request'
string_to_sign = algorithm + '\n' +  amz_date + '\n' +  credential_scope + '\n' +  hashlib.sha256(canonical_request.encode('utf-8')).hexdigest()

# ************* TASK 3: CALCULATE THE SIGNATURE *************
# Create the signing key using the function defined above.
signing_key = getSignatureKey(secret_key, date_stamp, region, service)

# Sign the string_to_sign using the signing_key
signature = hmac.new(signing_key, (string_to_sign).encode('utf-8'), hashlib.sha256).hexdigest()


# ************* TASK 4: ADD SIGNING INFORMATION TO THE REQUEST *************
# Put the signature information in a header named Authorization.
authorization_header = algorithm + ' ' + 'Credential=' + access_key + '/' + credential_scope + ', ' +  'SignedHeaders=' + signed_headers + ', ' + 'Signature=' + signature

# # Python note: The 'host' header is added automatically by the Python 'requests' library.
headers = {
       'Content-Type':content_type,
           'x-amzn-fragment-timecode-type': 'ABSOLUTE',
           'x-amzn-producer-start-timestamp': start_tmstp,
           'x-amzn-stream-name': 'ExampleStream', 
           'X-Amz-Target':amz_target,
           'x-amz-content-sha256':'UNSIGNED-PAYLOAD',
           'Authorization':authorization_header
           }


# ************* SEND THE REQUEST *************
print('\nBEGIN REQUEST++++++++++++++++++++++++++++++++++++')
print('Request URL = ' + endpoint)

r = requests.post(endpoint, data=request_parameters, headers=headers)

print('\nRESPONSE++++++++++++++++++++++++++++++++++++')
print('Response code: %d\n' % r.status_code)
print(r.text)

I have spent around a week on this issue. Please help me.

Sandeep Kumar
  • 41
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1 Answers1

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The input of PutMedia is not frames, you will need to provide MKV format input to it. You can refer to a similar example for PutMedia in java here: https://docs.aws.amazon.com/kinesisvideostreams/latest/dg/examples-putmedia.html

Zhiyuan
  • 64
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  • I have studied java and c++ examples code but couldn't understand how they works. Do I need to create a .mkv file by reading my cam? but then how a live streaming will be possible? Please guide! – Sandeep Kumar Aug 28 '18 at 05:07
  • You don't have to create an actual MKV file. Those examples were constructing MKV beforehand with GStreamer or similar media pipeline. You would need to create your own media pipeline to construct MKV stream using the frames from your camera. – Zhiyuan Aug 29 '18 at 20:47