If you want to get or manipulate the FLV metadata through Java program, this post will be very helpful for you. With this program you can get the details of FLV file like
1. Width
2. Height
3. Duration
4. Mime Type
5. File size
6. Video rate
7. Audio rate
8. Created date
I've not used any JARs or libraries to extract FLV metadata. It is a pure standalone Java program.
The technique is very simple. You need to read the raw bytes of the file and get the information that you would like to get.
Logic
1. Open FLV file's input stream
2. Read first 400 bytes and store them into a byte array
3. Create a string object from the byte array
4. Search for each FLV property like "duration", "width", "height" and etc.. get the index position.
5. From the index read 8 bytes and convert them as double.
Algorithm
START
PICK FLV file for which you would like metadata. This can be even a web URL
OPEN FLV file
READ first 400 Raw bytes from the file input stream
COVERT bytes into String
LOOP (This loop should be continued until you finish all your properties)
SEARCH for the property
IF FOUND
READ 8 bytes followed by the property name
DISPLAY or STORE the property
END IF
END LOOP
Here is the program that I've developed based on the above algorithm
FLVMetadata.java
import java.io.InputStream;
import java.io.FileInputStream;
import java.nio.ByteBuffer;
import java.net.URL;
import java.net.HttpURLConnection;
import java.text.DecimalFormat;
/**
* This class will get the FLV meta data information.
* @author SANTHOSH REDDY MANDADI
* @version 1.0
* @since 10th June 2009
*/
public class FLVMetaData
{
/**
* Represents the FLV path either a URL or a absolute file path. If it is URL
* url property should be true to access the file from web
*/
private String flv=null;
/**
* Represents whether the FLV is remote or local, if this is true
* data will be fetched through the HTTP connection otherwise data will
* be fetched from the local file.
*/
private boolean url=true;
//All the FLV properties
private String duration;
private double width;
private double height;
private double audioDataRate;
private double videoDataRate;
private double fileSize;
private String createdDate;
private String mimeType;
private double frameRate;
/**
* Constructs an object with flv as a url
* @param flv represents the web url
* @since 10-Jun-2009
*/
public FLVMetaData(String flv) throws Exception
{
this.flv=flv;
getMetaData();
}
/**
* Constructs an object with flv and boolean value url.
* @param flv represents the FLV path either a URL or a absolute file path.
* @param url represents boolean value.
*/
public FLVMetaData(String flv, boolean url) throws Exception
{
this.flv=flv;
this.url=url;
getMetaData();
}
/**
* Extract the metadata for the flv and sets them in the properties.
* If the property has 0.0 or null, then the information is not available on
* the target FLV.
* @throws Exception if something goes wrong.
*/
private void getMetaData() throws Exception
{
InputStream fis=null;
try{
if(url)
{
//Creating the URL object
URL url = new URL(flv);
//Establishing the connection to the server
HttpURLConnection connection=(HttpURLConnection)url.openConnection();
//Getting the remote input stream
fis=connection.getInputStream();
}
else
{
fis=new FileInputStream(flv);
}
//Creating the bytes array to read the first 400 bytes data from input stream
byte bytes[]=new byte[400];
//Reading the data from the input stream
fis.read(bytes);
/*Fetching the properties. If the output shows -1 or null then
consider that the FLV doesn't have that info on metadata*/
double duration=getDouble(bytes,"duration");
DecimalFormat f = new DecimalFormat("00");
setDuration(f.format((int)duration/60)+":"+f.format((int)duration%60));
setWidth(getDouble(bytes,"width"));
setHeight(getDouble(bytes,"height"));
setAudioDataRate(getDouble(bytes,"audiodatarate"));
setVideoDataRate(getDouble(bytes,"videodatarate"));
setFileSize(getDouble(bytes,"filesize"));
setCreatedDate(getString(bytes,"creationdate"));
setMimeType(getString(bytes,"mimetype"));
setFrameRate(getDouble(bytes,"framerate"));
//Closing the remote input stream
fis.close();
}catch(Exception e) {
throw new Exception(e);
}
finally {
if(fis!=null) {
fis.close();
}
}
}
private double getDouble(byte[] bytes, String property)
{
//Creating a string from the bytes
String metaData=new String(bytes);
//Checking whether the property exists on the metadata
int offset=metaData.indexOf(property);
if(offset!=-1)
{
//Calculating the value from the bytes received from getBytes method
return ByteBuffer.wrap(getBytes(bytes, offset+property.length()+1, 8)).getDouble();
}
else
{
//Returning -1 to notify the info not available
return -1;
}
}
private String getString(byte[] bytes, String property)
{
//Creating a string from the bytes
String metaData=new String(bytes);
//Checking whether the property exists on the metadata
int offset=metaData.indexOf(property);
if(offset!=-1)
{
//Constructing the string from the bytes received from getBytes method
return new String(getBytes(bytes, offset+property.length()+3, 24));
}
else
{
//Returning null to notify the info not available
return null;
}
}
private byte[] getBytes(byte[] bytes, int offset, int length)
{
//Fetching the required number of bytes from the source and returning
byte requiredBytes[]=new byte[length];
for(int i=offset, j=0;j<length;i++,j++)
{
requiredBytes[j]=bytes[i];
}
return requiredBytes;
}
public void setFlv(String flv)
{
this.flv = flv;
}
public String getFlv()
{
return flv;
}
public void setUrl(boolean url)
{
this.url = url;
}
public boolean isUrl()
{
return url;
}
public void setCreatedDate(String createdDate)
{
this.createdDate = createdDate;
}
public String getCreatedDate()
{
return createdDate;
}
public void setMimeType(String mimeType)
{
this.mimeType = mimeType;
}
public String getMimeType()
{
return mimeType;
}
public void setWidth(double width)
{
this.width = width;
}
public double getWidth()
{
return width;
}
public void setHeight(double height)
{
this.height = height;
}
public double getHeight()
{
return height;
}
public void setAudioDataRate(double audioDataRate)
{
this.audioDataRate = audioDataRate;
}
public double getAudioDataRate()
{
return audioDataRate;
}
public void setVideoDataRate(double videoDataRate)
{
this.videoDataRate = videoDataRate;
}
public double getVideoDataRate()
{
return videoDataRate;
}
public void setFileSize(double fileSize)
{
this.fileSize = fileSize;
}
public double getFileSize()
{
return fileSize;
}
public void setFrameRate(double frameRate)
{
this.frameRate = frameRate;
}
public double getFrameRate()
{
return frameRate;
}
public void setDuration(String duration)
{
this.duration = duration;
}
public String getDuration()
{
return duration;
}
public static void main(String args[]) throws Exception
{
FLVMetaData metaData=new FLVMetaData("http://domain/o18/HCINTL/LIVE/72224/myhc_200.flv");
System.out.println(metaData.getDuration());
metaData.setUrl(false);
metaData.setFlv("1.flv");
metaData.getMetaData();
System.out.println(metaData.getDuration());
}
}
Above program has been compiled and tested on JDK 1.4 and 1.5.
Click here to check out other programs that I've developed.