Google Cloud Speech API using php
<p>I am trying to call Google Cloud Speech API by using PHP and got a problem.</p>

<pre><code>$stturl = "https://speech.googleapis.com/v1beta1/speech:syncrecognize?key=xxxxxxxxxxxx";
$upload = file_get_contents("1.wav");
$upload = base64_encode($upload);

$data = array(
    "config"    =&gt;  array(
        "encoding"      =&gt;  "LINEAR16",
        "sampleRate"    =&gt;  16000,
        "languageCode"  =&gt;  "en-US"
    ),
    "audio"     =&gt;  array(
        "Content"       =&gt;  $upload,
    )
);

$jsonData = json_encode($data);

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $stturl);
curl_setopt($ch, CURLOPT_HTTPHEADER, array("Content-Type: application/json"));
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, $jsonData);

$result = curl_exec($ch);
</code></pre>

<p>The result says that it is INVALID JSON PAYLOAD.</p>

<blockquote>
  <p>{ "error": { "code": 400, "message": "Invalid JSON payload received.
  Unknown name \"content\" at 'audio': Cannot find field.", "status":
  "INVALID_ARGUMENT", "details": [ { "@type":
  "type.googleapis.com/google.rpc.BadRequest", "fieldViolations": [ {
  "field": "audio", "description": "Invalid JSON payload received.
  Unknown name \"content\" at 'audio': Cannot find field." } ] } ] } } "</p>
</blockquote>

<p>I think this is because $upload isn't configured correctly.
According Google Cloud Speech API, it should be "A base64-encoded string".
<a href="https://cloud.google.com/speech/reference/rest/v1beta1/RecognitionAudio" rel="nofollow">https://cloud.google.com/speech/reference/rest/v1beta1/RecognitionAudio</a></p>

<p>That's why I used <strong>base64_encode</strong> function, but it seems JSON doesn't process this value correctly.
Any thoughts?</p>