给出ffmpeg可以对byte[]进行编码的demo

下面是一个使用ffmpeg对byte[]进行编码的示例代码：

import org.bytedeco.ffmpeg.global.avcodec;
import org.bytedeco.ffmpeg.global.avutil;
import org.bytedeco.javacpp.BytePointer;
import org.bytedeco.javacpp.Pointer;
import org.bytedeco.javacpp.avcodec.AVPacket;
import org.bytedeco.javacpp.avcodec.AVCodec;
import org.bytedeco.javacpp.avcodec.AVCodecContext;
import org.bytedeco.javacpp.avcodec.AVFrame;
import org.bytedeco.javacpp.avutil.AVDictionary;
import org.bytedeco.javacpp.avutil.AVFrameRef;
import org.bytedeco.javacpp.avutil.AVRational;
import org.bytedeco.javacpp.avutil.AVSampleFormat;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;

public class FFmpegEncoderDemo {
    private static final int SAMPLE_RATE = 44100;
    private static final int CHANNELS = 2;
    private static final int BIT_RATE = 64000;
    private static final int FRAME_SIZE = 1024;
    private static final AVRational TIME_BASE = new AVRational().num(1).den(SAMPLE_RATE);

    public static void main(String[] args) {
        // 初始化AVCodec和AVCodecContext
        AVCodec codec = avcodec.avcodec_find_encoder(avcodec.AV_CODEC_ID_MP3);
        AVCodecContext context = avcodec.avcodec_alloc_context3(codec);
        context.sample_rate(SAMPLE_RATE);
        context.channels(CHANNELS);
        context.bit_rate(BIT_RATE);
        context.channel_layout(avutil.av_get_default_channel_layout(CHANNELS));
        context.sample_fmt(AVSampleFormat.AV_SAMPLE_FMT_S16);
        avcodec.avcodec_open2(context, codec, new AVDictionary(null));

        // 创建AVFrame和AVPacket
        AVFrame frame = avutil.av_frame_alloc();
        frame.sample_rate(SAMPLE_RATE);
        frame.channels(CHANNELS);
        frame.format(context.sample_fmt());
        frame.nb_samples(FRAME_SIZE);
        avutil.av_frame_get_buffer(frame, 0);
        AVPacket packet = avcodec.av_packet_alloc();

        // 构造测试数据
        byte[] data = new byte[FRAME_SIZE * CHANNELS * 2];
        ByteBuffer buffer = ByteBuffer.wrap(data).order(ByteOrder.LITTLE_ENDIAN);
        for (int i = 0; i < FRAME_SIZE; i++) {
            buffer.putShort((short) (32767 * Math.sin(2 * Math.PI * i / FRAME_SIZE)));
            buffer.putShort((short) (32767 * Math.cos(2 * Math.PI * i / FRAME_SIZE)));
        }

        // 将byte[]编码为MP3格式
        frame.data(0, new BytePointer(data));
        frame.pts(0);
        while (true) {
            int ret = avcodec.avcodec_send_frame(context, frame);
            if (ret < 0) {
                break;
            }
            while (ret >= 0) {
                ret = avcodec.avcodec_receive_packet(context, packet);
                if (ret == avutil.AVERROR_EAGAIN() || ret == avutil.AVERROR_EOF()) {
                    break;
                }
                if (ret < 0) {
                    throw new RuntimeException("Error encoding audio: " + ret);
                }
                // 处理编码后的数据
                System.out.println("Encoded packet with size " + packet.size());
            }
        }
        avcodec.avcodec_send_frame(context, null);
        while (true) {
            int ret = avcodec.avcodec_receive_packet(context, packet);
            if (ret == avutil.AVERROR_EAGAIN() || ret == avutil.AVERROR_EOF()) {
                break;
            }
            if (ret < 0) {
                throw new RuntimeException("Error encoding audio: " + ret);
            }
            // 处理编码后的数据
            System.out.println("Encoded packet with size " + packet.size());
        }

        // 释放资源
        avcodec.av_packet_free(packet);
        avutil.av_frame_free(frame);
        avcodec.avcodec_free_context(context);
    }
}

这个示例代码使用了JavaCPP和JavaCV库来调用ffmpeg的函数进行编码。你需要先在你的项目中添加这两个库的依赖，然后就可以使用上面的代码对byte[]进行编码了。注意，这个代码只是一个示例，你需要根据自己的需求进行修改。