Base64 Encoding

When passing video to the Video Intelligence API, you can either pass a Cloud Storage URI, or you can embed video data directly within the request's content field, which must be base64 encoded.

Using the command line

Within a gRPC request, you can simply write binary data out directly; however, JSON is used when making a REST request. JSON is a text format that does not directly support binary data, so you will need to convert such binary data into text using Base64 encoding.

Most development environments contain a native base64 utility to encode a binary into ASCII text data. To encode a file:

Linux

Encode the file using the base64 command line tool, making sure to prevent line-wrapping by using the -w 0 flag:

base64 INPUT_FILE 
-w 0 > OUTPUT_FILE

macOS

Encode the file using the base64 command line tool:

base64 -i INPUT_FILE 
-o OUTPUT_FILE

Windows

Encode the file using the Base64.exe tool:

certutil -encodehex SOURCE_VIDEO_FILE 
> DEST_TEXT_FILE 
0x40000001

PowerShell

Encode the file using the Convert.ToBase64String method:

[Convert]::ToBase64String([IO.File]::ReadAllBytes("./ INPUT_FILE 
")) > OUTPUT_FILE

Create a JSON request file, inlining the base64-encoded data:

JSON

 { 
  
 "requests" 
 :[ 
  
 { 
  
 "image" 
 :{ 
  
 "content" 
 : 
  
 "ZkxhQwAAACIQABAAAAUJABtAA+gA8AB+W8FZndQvQAyjv..." 
  
 }, 
  
 "features" 
 : 
  
 [ 
  
 { 
  
 "type" 
 : 
 "LABEL_DETECTION" 
 , 
  
 "maxResults" 
 : 
 1 
  
 } 
  
 ] 
  
 } 
  
 ] 
 }

Using client libraries

Embedding binary data into requests through text editors is neither desirable or practical. In practice, you will be embedding base64 encoded files within client code. All supported programming languages have built-in mechanisms for base64 encoding content.

Python

In Python, base64 encode video files as follows:

  # Import the base64 encoding library. 
 import 
  
 base64 
 # Pass the video data to an encoding function. 
 def 
  
 encode_video 
 ( 
 video 
 ): 
 video_content 
 = 
 video 
 . 
 read 
 () 
 return 
 base64 
 . 
 b64encode 
 ( 
 video_content 
 )

Node.js

In Node.js, base64 encode video files as follows:

  // Read the file into memory. 
 var 
  
 fs 
  
 = 
  
 require 
 ( 
 'fs' 
 ); 
 var 
  
 videoFile 
  
 = 
  
 fs 
 . 
 readFileSync 
 ( 
 '/path/to/file' 
 ); 
 // Convert the video data to a Buffer and base64 encode it. 
 var 
  
 encoded 
  
 = 
  
 new 
  
 Buffer 
 ( 
 videoFile 
 ). 
 toString 
 ( 
 'base64' 
 );

Java

In Java, you can base64 encode image files as follows:

  // Import the Base64 encoding library. 
 import 
  
 org.apache.commons.codec.binary.Base64 
 ; 
 // Encode the video. 
 byte 
 [] 
  
 videoData 
  
 = 
  
 Base64 
 . 
 encodeBase64 
 ( 
 videoFile 
 . 
 getBytes 
 ());