Google Speech API"请求中的采样率与FLAC标头不匹配"

Question

我正在尝试将mp4视频片段转换为FLAC音频文件,然后谷歌语音吐出视频中的单词,以便我可以检测是否有特定的单词.

除了我从Speech API收到错误之外,我已经完成了所有工作:

{
  "error": {
    "code": 400,
    "message": "Sample rate in request does not match FLAC header.",
    "status": "INVALID_ARGUMENT"
  }
}

我正在使用FFMPEG将mp4转换为FLAC文件.我在命令中指定FLAC文件为16位,但是当我右键单击FLAC文件时,Windows告诉我它是302kbps.

这是我的PHP代码:

// convert mp4 video to 16 bit flac audio file
$cmd = 'C:/wamp/www/ffmpeg/bin/ffmpeg.exe -i C:/wamp/www/test.mp4 -c:a flac -sample_fmt s16 C:/wamp/www/test.flac';
exec($cmd, $output);

// convert flac to text so we can detect if certain words were said
$data = array(
    "config" => array(
        "encoding" => "FLAC",
        "sampleRate" => 16000,
        "languageCode" => "en-US"
    ),
    "audio" => array(
        "content" => base64_encode(file_get_contents("test.flac")),
    )
);

$json_data = json_encode($data);

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, 'https://speech.googleapis.com/v1beta1/speech:syncrecognize?key=MY_API_KEY');
curl_setopt($ch, CURLOPT_HTTPHEADER, array("Content-Type: application/json"));
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, $json_data);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);

$result = curl_exec($ch);

Answer 1

通过在我的FFMPEG命令中非常具体来修复它:

$cmd = 'C:/wamp/www/ffmpeg/bin/ffmpeg.exe -i C:/wamp/www/test.mp4 -acodec flac -bits_per_raw_sample 16 -ar 44100 -ac 1 C:/wamp/www/test.flac';