首先我们来看java端代码
while (mOpened) {
try {
int read = mInputStream.read(buffer);
if (read != 0 && read > 0) {
if (mOnReceivedListener == null)
return;
byte[] bytes = Arrays.copyOf(buffer, read);
mOnReceivedListener.onReceived(bytes);
}
} catch (IOException e) {
e.printStackTrace();
errorCount++;
}
if (errorCount > 5) {
try {
close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
因为我这里是通过usb端口aoa协议拿到码流实现一个长链关系的。我们写入流之后就可以来看c方面的处理了。
int i, videoindex;
int retry_time = 0;
if (ad == NULL)
ad = (AndroidDisplay *) av_mallocz(sizeof(AndroidDisplay));
jclass wc = env->FindClass("com/.../MainActivity");
if (wc == 0) {
LOGE("Could not find com.....MainActivity class !");
}
//拿到java层中读取的码流缓存的方法
ad->j_sync_stream = env->GetMethodID(wc, "syncStream", "([BI)I");
if (ad->j_sync_stream == 0)
LOGE("Could not find 'syncStream' method\n");
if (id) {
ad->android_video_window = (env)->NewGlobalRef(id);
} else
ad->android_video_window = NULL;
env->DeleteLocalRef(wc);
//声明一个缓存空间
buf = (uint8_t *) av_mallocz(BUF_SIZE);
av_log_set_callback(ffmpeg_log_handler);
//初始化
avcodec_register_all();
av_register_all();
// avio_alloc_context开头会读取部分数据探测流的信息,不会全部读取， 除非设置的缓存过大 av_read_frame会在读帧的时候调用avio_alloc_context中的 read_packet方法取流数据，每隔avio_ctx_buffer_size调用一次，直至读完
pb = avio_alloc_context(buf, BUF_SIZE, 0, NULL, av_read_data, NULL, NULL);
if (pb == NULL)
LOGE("avio_alloc_context失败了!!!");
bool inital_ok = false;
while (!inital_ok) {
piFmt = NULL;
if (av_probe_input_buffer(pb, &piFmt, NULL, NULL, 0,32 * 1024) < 0) {
LOGE("av_probe_input_buffer 失败!\n");
continue;
} else {
LOGE("av_probe_input_buffer 成功!\n");
}
pFormatCtx = avformat_alloc_context();
pFormatCtx->pb = pb;
while (avformat_open_input(&pFormatCtx, "", piFmt, NULL) != 0) {
LOGE("无法打开输入流\n");
continue;
}
videoindex = -1;
for (i = 0; i < pFormatCtx->nb_streams; i++)
if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
videoindex = i;
break;
}
if (videoindex == -1) {
LOGE("无法找到视频流.\n");
continue;
}
pCodecCtx = pFormatCtx->streams[videoindex]->codec;
if (pCodecCtx->width == 0 || pCodecCtx->height == 0) {
pCodecCtx->width = 1280;
pCodecCtx->height = 720;
}
if (pCodecCtx != NULL)
LOGE("pCodecCtx is not NULL!\n");
pCodec = avcodec_find_decoder(pCodecCtx->codec_id);
if (pCodec == NULL) {
LOGE("Couldn't find Codec.\n");
continue;
}
LOGE("Stream Size is %d x %d \n", pCodecCtx->width, pCodecCtx->height);
if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0) {
LOGE("Couldn't open codec.\n");
continue;
}
LOGE("Now Stream Size is %d x %d \n", pCodecCtx->width, pCodecCtx->height);
inital_ok = true;
// 获取native window
ANativeWindow *nativeWindow = ANativeWindow_fromSurface(env, surface);
// 获取视频宽高
int videoWidth = pCodecCtx->width;
int videoHeight = pCodecCtx->height;
// 设置native window的buffer大小,可自动拉伸
ANativeWindow_setBuffersGeometry(nativeWindow, videoWidth, videoHeight,
WINDOW_FORMAT_RGBA_8888);
ANativeWindow_Buffer windowBuffer;
// Allocate video frame
AVFrame *pFrame = av_frame_alloc();
// 用于渲染
AVFrame *pFrameRGBA = av_frame_alloc();
if (pFrameRGBA == NULL || pFrame == NULL) {
LOGE("Could not allocate video frame.");
return;
}
// Determine required buffer size and allocate buffer
// buffer中数据就是用于渲染的,且格式为RGBA
int numBytes = av_image_get_buffer_size(AV_PIX_FMT_RGBA, pCodecCtx->width, pCodecCtx->height,
1);
uint8_t *buffer = (uint8_t *) av_malloc(numBytes * sizeof(uint8_t));
av_image_fill_arrays(pFrameRGBA->data, pFrameRGBA->linesize, buffer, AV_PIX_FMT_RGBA,
pCodecCtx->width, pCodecCtx->height, 1);
// 由于解码出来的帧格式不是RGBA的,在渲染之前
// 需要进行格式转换
struct SwsContext *sws_ctx = sws_getContext(pCodecCtx->width,
pCodecCtx->height,
AV_PIX_FMT_YUV420P,
pCodecCtx->width,
pCodecCtx->height,
AV_PIX_FMT_RGBA,
SWS_BILINEAR,
NULL,
NULL,
NULL);
int frameFinished;
AVPacket packet;
while (av_read_frame(pFormatCtx, &packet) >= 0) {
// Is this a packet from the video stream?
if (packet.stream_index == videoindex) {
// Decode video frame
avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet);
// 并不是decode一次就可解码出一帧
if (frameFinished) {
// lock native window buffer
ANativeWindow_lock(nativeWindow, &windowBuffer, 0);
// 格式转换
sws_scale(sws_ctx, (uint8_t const *const *) pFrame->data,
pFrame->linesize, 0, pCodecCtx->height,
pFrameRGBA->data, pFrameRGBA->linesize);
// 获取stride
uint8_t *dst = (uint8_t *) windowBuffer.bits;
int dstStride = windowBuffer.stride * 4;
uint8_t *src = (pFrameRGBA->data[0]);
int srcStride = pFrameRGBA->linesize[0];
// 由于window的stride和帧的stride不同,因此需要逐行复制
int h;
for (h = 0; h < videoHeight; h++) {
memcpy(dst + h * dstStride, src + h * srcStride, srcStride);
}
ANativeWindow_unlockAndPost(nativeWindow);
}
}
av_packet_unref(&packet);
}
av_free(buffer);
av_free(pFrameRGBA);
// Free the YUV frame
av_free(pFrame);
// Close the codecs
avcodec_close(pCodecCtx);
// Close the video file
avformat_close_input(&pFormatCtx);
这里需要注意的是读视频流的时候可能会丢失pCodecCtx的一些参数，如果丢失程序会发生崩溃，我这边就遇到了丢失了视频的宽高，还有视频的格式参数等等。。。暂时还不确定为什么会丢失。所以总结就是我们只需要把码流和SurfaceView传过来，当有码流存在的时候使用while循环进行一个长链接就行了，第一次分享，可能说的不太清楚。。。欢迎指导