Android 使用ffmpeg软编码 将摄像头采集视频编码成视频文件
Android 使用ffmpeg软编码 将摄像头采集视频编码成视频文件。
这次代码实现的是视频采集的功能，Android 通过jni 调用ffmpeg 编码yuv数据变成视频文件。
先上代码：
//编码器上下文保存的实体
struct EnCodeBean {
FILE *f;
AVFrame *frame;
AVPacket *pkt;
AVCodecContext *c = NULL;
int width=0;
int height=0;
};
EnCodeBean *videoEncodeObj = NULL;
//编码每一帧
static void encode(AVCodecContext *enc_ctx, AVFrame *frame, AVPacket *pkt,
FILE *outfile);
//初始化编码器
static jint initEnCodec(JNIEnv *env, jobject jobject1, jstring path, jint w, jint h) {
videoEncodeObj = new EnCodeBean;
char filename[300], *codec_name;
const AVCodec *codec;
int i, ret, x, y;
uint8_t endcode[] = {0, 0, 1, 0xb7};
char errorArr[500];
videoEncodeObj->width=w;
videoEncodeObj->height=h;
// filename = "/storage/emulated/0/Download/jason_video.h265";
//获取路径参数
const char *_path = env->GetStringUTFChars(path, 0);
sprintf(filename, "%s", _path);
env->ReleaseStringUTFChars(path, _path);
AVCodecID videoCodec = AV_CODEC_ID_MPEG2VIDEO; // 编码器类型
/* 查找编码器 */
codec = avcodec_find_encoder(videoCodec);
LOGJASON(FMT_TAG, avcodec_get_name(videoCodec));
if (!codec) {
sprintf(errorArr, "Codec '%s' not found\n", avcodec_get_name(videoCodec));
LOGJASON(FMT_TAG, errorArr);
return -1;
}
//编码上下文
videoEncodeObj->c = avcodec_alloc_context3(codec);
if (!videoEncodeObj->c) {
sprintf(errorArr, "Could not allocate video codec context\n");
LOGJASON(FMT_TAG, errorArr);
return -1;
}
//编码后存储的包packet
videoEncodeObj->pkt = av_packet_alloc();
if (!videoEncodeObj->pkt) {
sprintf(errorArr, "packet init error\n");
LOGJASON(FMT_TAG, errorArr);
return -1;
}
/* 设置参数 */
videoEncodeObj->c->bit_rate = 639 * 1000;//码率 质量
/* resolution must be a multiple of two */
videoEncodeObj->c->width = w;
videoEncodeObj->c->height = h;
/* frames per second */
videoEncodeObj->c->time_base = (AVRational) {1, 25};//时间单位 时基
videoEncodeObj->c->framerate = (AVRational) {25, 1};//频率
videoEncodeObj->c->gop_size = 10;
videoEncodeObj->c->max_b_frames = 1;
videoEncodeObj->c->pix_fmt = AV_PIX_FMT_YUV420P;//图像格式
if (codec->id == AV_CODEC_ID_H264)
av_opt_set(videoEncodeObj->c->priv_data, "preset", "slow", 0);
/* 打开编码器 */
ret = avcodec_open2(videoEncodeObj->c, codec, NULL);
if (ret < 0) {
sprintf(errorArr, "Could not open codec: %s\n", av_err2str(ret));
LOGJASON(FMT_TAG, errorArr);
return -1;
}
//打开创建文件
videoEncodeObj->f = fopen(filename, "wb");
if (!videoEncodeObj->f) {
sprintf(errorArr, "Could not open %s\n", filename);
LOGJASON(FMT_TAG, errorArr);
return -1;
}
//每帧储存内存创建
videoEncodeObj->frame = av_frame_alloc();
if (!videoEncodeObj->frame) {
sprintf(errorArr, "Could not allocate video frame\n");
LOGJASON(FMT_TAG, errorArr);
return -1;
}
videoEncodeObj->frame->format = videoEncodeObj->c->pix_fmt;
videoEncodeObj->frame->width = videoEncodeObj->c->width;
videoEncodeObj->frame->height = videoEncodeObj->c->height;
//根据参数构建buf
ret = av_frame_get_buffer(videoEncodeObj->frame, 32);//32
if (ret < 0) {
sprintf(errorArr, "Could not allocate the video frame data\n");
LOGJASON(FMT_TAG, errorArr);
return -1;
}
LOGJASON("init ok %p", videoEncodeObj);
return 0;
}
//编码每一帧
static void encode(AVCodecContext *enc_ctx, AVFrame *frame, AVPacket *pkt,
FILE *outfile) {
int ret;
char errorStr[500];
/* send the frame to the encoder */
if (frame)
LOGJASON("Send frame %lld\n", frame->pts);
//开始编码
ret = avcodec_send_frame(enc_ctx, frame);
if (ret < 0) {
sprintf(errorStr, "Error sending a frame for encoding\n");
LOGJASON(FMT_TAG, errorStr);
return;
}
while (ret >= 0) {
//接受编码
ret = avcodec_receive_packet(enc_ctx, pkt);
if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
return;
else if (ret < 0) {
sprintf(errorStr, "Error during encoding\n");
LOGJASON(FMT_TAG, errorStr);
return;
}
LOGJASON("Write packet %lld (size=%5d)\n", pkt->pts, pkt->size);
//写入文件
fwrite(pkt->data, 1, pkt->size, outfile);
av_packet_unref(pkt);
}
}
//Java推送流的编码方法
static jint pushFrame(JNIEnv *env, jobject jobject1, jlong pts, jbyteArray jbyteArray1) {
//获取yuv 流
int len=env->GetArrayLength(jbyteArray1);
unsigned char *buf = new unsigned char[len];
env->GetByteArrayRegion(jbyteArray1, 0, len, reinterpret_cast<jbyte *>(buf));
/* make sure the frame data is writable */
int i, ret;
char errorArr[500];
i = pts;
ret = av_frame_make_writable(videoEncodeObj->frame);
if (ret < 0) {
sprintf(errorArr, "av_frame_make_writable is error");
LOGJASON(FMT_TAG, errorArr);
return -1;
}
int frameSize = videoEncodeObj->width*videoEncodeObj->height;
//将流数据复制进入frame buffer
memcpy(videoEncodeObj->frame->data[0], buf, frameSize);
memcpy(videoEncodeObj->frame->data[1], buf+frameSize, frameSize/4);
memcpy(videoEncodeObj->frame->data[2], buf+frameSize+frameSize/4, frameSize/4);
videoEncodeObj->frame->pts = i;
/* 开始编码 */
encode(videoEncodeObj->c, videoEncodeObj->frame, videoEncodeObj->pkt, videoEncodeObj->f);
//释放引用
env->ReleaseByteArrayElements(jbyteArray1, reinterpret_cast<jbyte *>(buf), 0);
return 0;
}
//关闭编码功能
static jint endClose(JNIEnv *env, jobject jobject1) {
uint8_t endcode[] = {0, 0, 1, 0xb7};
/* 清空缓存区 */
encode(videoEncodeObj->c, NULL, videoEncodeObj->pkt, videoEncodeObj->f);
/* 写入文件尾部 */
fwrite(endcode, 1, sizeof(endcode), videoEncodeObj->f);
fclose(videoEncodeObj->f);
//释放上下文
avcodec_free_context(&videoEncodeObj->c);
av_frame_free(&videoEncodeObj->frame);
av_packet_free(&videoEncodeObj->pkt);
LOGJASON("is end ok");
delete videoEncodeObj;
videoEncodeObj = NULL;
LOGJASON("free out is ok");
return 0;
}
static jint showMsg(JNIEnv *env, jobject jobject1, jstring jstring1) {
const char *instr = env->GetStringUTFChars(jstring1, 0);
LOGJASON(FMT_TAG, instr);
env->ReleaseStringUTFChars(jstring1, instr);
return 0;
}
//----------------------------------jni 动态注册方法-----------------------------------------
static JNINativeMethod javaMethods[] = {
{"initEnCodec", "(Ljava/lang/String;II)I", (void *) initEnCodec},
{"pushFrame", "(J[B)I", (void *) pushFrame},
{"showMsg", "(Ljava/lang/String;)I", (void *) showMsg},
{"endClose", "()I", (void *) endClose}
};
jint JNI_OnLoad(JavaVM *vm, void *unused) {
JNIEnv *env = NULL;
if (vm->GetEnv((void **) &env, JNI_VERSION_1_4) != JNI_OK) {
LOGJASON(FMT_TAG, "和获取env异常");
return -1;
}
const char *className = "com/liyihang/jason/VideoEnCodec";
int methodNum = sizeof(javaMethods) / sizeof(JNINativeMethod);
jclass jclass1 = env->FindClass(className);
if (jclass1 == NULL) {
LOGJASON(FMT_TAG, "find class error");
return -1;
}
int ret = env->RegisterNatives(jclass1, javaMethods, methodNum);
if (ret < 0) {
env->DeleteLocalRef(jclass1);
return -1;
}
env->DeleteLocalRef(jclass1);
return JNI_VERSION_1_4;
}
Java调用 so库文件：
public class VideoEnCodec {
static {
System.loadLibrary("native-lib");
}
public native int initEnCodec(String path, int w, int h);
public native int pushFrame(long pts,byte[] arr);
public native int endClose();
public native int showMsg(String msg);
}
调用方法：
//必须在子线程中运行
private void handle() {
int w=320;
int h=240;
VideoEnCodec videoEnCodec = new VideoEnCodec();
//初始化 和 关闭必须成对出现
videoEnCodec.initEnCodec("/storage/emulated/0/Download/jason_video3.h265", w,h);
for (int i = 0; i < 90; i++) {
//推送摄像头采集的每一帧 例如：camera 采集的nv21 数据 i 是pts
byte[] arr = makeBuf(w,h, i);
videoEnCodec.pushFrame(i,arr);
}
//关闭编码器
videoEnCodec.endClose();
}
//构建yuv假数据
private byte[] makeBuf(int w, int h, int i){
/* prepare a dummy image */
int y,x;
byte[] arr=new byte[w*h+(w*h)/2];
/* Y */
int offset=0;
for (y = 0; y < h; y++) {
for (x = 0; x < w; x++) {
arr[offset]= (byte)
(x + y + i * 3);
offset++;
}
}
/* Cb and Cr */
for (y = 0; y < h / 2; y++) {
for (x = 0; x < w / 2; x++) {
arr[offset]= (byte) (128 + y + i * 2);
arr[offset+(w*h/4)]= (byte) (64 + x + i * 5);
offset++;
}
}
return arr;
}
这里为了方便理解没有适用任何封装，采集摄像头的数据可以看看我的博客中关于摄像头采集这块的文章，这里我们方便理解手动造出了每帧的图像数据。
代码中也有有详细主是可以方便理解。
代码补充：
#include 接下来还会更新 声音采集，如果有兴趣可以继续关注我的博客。
关于Android jni ffmpeg 环境搭建可以参考我博客中其他文章， 网上这类文章很多就不在重复了
转载时候一定要注明出处 尊重原创 谢谢！