src/main/java/org/jcodec/api/FrameGrab.java
public static Picture getNativeFrameAtFrame(SeekableDemuxerTrack vt, ContainerAdaptor decoder, int frameNumber)
            throws IOException, JCodecException {
        return new FrameGrab(vt, decoder).seekToFramePrecise(frameNumber).getNativeFrame();
    }
public static Picture getNativeFrameAtFrame(SeekableDemuxerTrack vt, ContainerAdaptor decoder, int frameNumber)
            throws IOException, JCodecException {
        return new FrameGrab(vt, decoder).seekToFramePrecise(frameNumber).getNativeFrame();
    }
public static Picture getNativeFrameAtFrame ( SeekableDemuxerTrack vt , ContainerAdaptor decoder , int frameNumber ) throws IOException , JCodecException { return new FrameGrab ( vt , decoder ) . seekToFramePrecise ( frameNumber ) . getNativeFrame ( ) ; }
Get a specified frame by number from an already open demuxer track

@param vt
@param decoder
@param frameNumber
@return
@throws IOException
@throws JCodecException
Get a specified frame by number from an already open demuxer track