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前面写了视频解码和音频解码，接下来要同步了
java代码
setContentView(R.layout.activity_main); SurfaceView surfaceView = findViewById(R.id.surface_view); surfaceView.getHolder().addCallback(new SurfaceHolder.Callback() {@Override public void surfaceCreated(SurfaceHolder holder) {}@Override public void surfaceChanged(final SurfaceHolder holder, int format, int width, int height) {Thread audioThread = new Thread(){@Override public void run() {super.run(); String videoPath = "/storage/emulated/0/baiduNetdisk/season09.mp4"; audioPlay(videoPath); }}; audioThread.start(); Thread videoThread = new Thread(){@Override public void run() {super.run(); String videoPath = "/storage/emulated/0/baiduNetdisk/season09.mp4"; videoPlay(videoPath,holder.getSurface()); }}; videoThread.start(); }@Override public void surfaceDestroyed(SurfaceHolder holder) {} });就是开两个线程主要还是c++代码
既然要同步线程，肯定是让快的线程等待慢的线程，通过前面的代码知道，视频线程比音频快，所以只能让视频线程进行等待，等待的话就用到了锁
pthread_mutex_t video_mutex; pthread_cond_t video_cond;还需要等待时间
long audio_time = 0; long start_time = 0;
知道当前时间
long getCurrentTime() {struct timeval tv; gettimeofday(&tv,NULL); return tv.tv_sec * 1000 + tv.tv_usec / 1000; }计算等待时间的方法
timespec waitTime(long timeout_ms){struct timespec abstime; struct timeval now; gettimeofday(&now, NULL); long nsec = now.tv_usec * 1000 + (timeout_ms % 1000) * 1000000; abstime.tv_sec=now.tv_sec + nsec / 1000000000 + timeout_ms / 1000; abstime.tv_nsec=nsec % 1000000000; return abstime; }首先，要在音频线程计算出音频的时间
double nowTime = frame->pts * av_q2d(avStream->time_base); long t = (long) (nowTime * 1000); audio_time = t; start_time = getCurrentTime();然后在视频线程计算出时间差
double nowTime = yuvFrame->pts * av_q2d(avStream->time_base); long t = (long) (nowTime * 1000); long time = getCurrentTime() - start_time; long wait = t - time - audio_time;再让视频线程进行等待
struct timespec abstime = waitTime(wait); pthread_mutex_lock(&video_mutex); pthread_cond_timedwait(&video_cond, &video_mutex,&abstime); pthread_mutex_unlock(&video_mutex);这样就实现时间同步，误差是一定有的，几毫秒到十几毫秒吧
贴完整代码
pthread_mutex_t video_mutex; pthread_cond_t video_cond; long audio_time = 0; long start_time = 0; long getCurrentTime() {struct timeval tv; gettimeofday(&tv,NULL); return tv.tv_sec * 1000 + tv.tv_usec / 1000; }timespec waitTime(long timeout_ms){struct timespec abstime; struct timeval now; gettimeofday(&now, NULL); long nsec = now.tv_usec * 1000 + (timeout_ms % 1000) * 1000000; abstime.tv_sec=now.tv_sec + nsec / 1000000000 + timeout_ms / 1000; abstime.tv_nsec=nsec % 1000000000; return abstime; }extern "C" JNIEXPORT void JNICALL Java_com_example_ffmpegrun_MainActivity_videoPlay(JNIEnv *env, jobject instance, jstring path_, jobject surface) {const char *path = env->GetStringUTFChars(path_, 0); // TODO pthread_mutex_init (&video_mutex,NULL); pthread_cond_init(&video_cond,NULL); av_register_all(); AVFormatContext *fmt_ctx = avformat_alloc_context(); if (avformat_open_input(&fmt_ctx, path, NULL, NULL) < 0) {return; }if (avformat_find_stream_info(fmt_ctx, NULL) < 0) {return; }AVStream *avStream = NULL; int video_stream_index = -1; for (int i = 0; i < fmt_ctx->nb_streams; i++) {if (fmt_ctx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {avStream = fmt_ctx->streams[i]; video_stream_index = i; break; }}if (video_stream_index == -1) {return; }AVCodecContext *codec_ctx = avcodec_alloc_context3(NULL); avcodec_parameters_to_context(codec_ctx, avStream->codecpar); AVCodec *avCodec = avcodec_find_decoder(codec_ctx->codec_id); if (avcodec_open2(codec_ctx, avCodec, NULL) < 0) {return; }ANativeWindow* nativeWindow = ANativeWindow_fromSurface(env,surface); AVFrame *yuvFrame = av_frame_alloc(); EGLUtils *eglUtils = new EGLUtils(); eglUtils->initEGL(nativeWindow); OpenGLUtils *openGLUtils = new OpenGLUtils(); openGLUtils->surfaceCreated(); openGLUtils->surfaceChanged(eglUtils->getWidth(),eglUtils->getHeight()); openGLUtils->initTexture(codec_ctx->width,codec_ctx->height); int y_size = codec_ctx->width * codec_ctx->height; AVPacket *pkt = (AVPacket *) malloc(sizeof(AVPacket)); av_new_packet(pkt, y_size); int ret; while (1) {if (av_read_frame(fmt_ctx, pkt) < 0) {av_packet_unref(pkt); break; }if (pkt->stream_index == video_stream_index) {ret = avcodec_send_packet(codec_ctx, pkt); if (ret < 0 && ret != AVERROR(EAGAIN) && ret != AVERROR_EOF) {av_packet_unref(pkt); continue; }ret = avcodec_receive_frame(codec_ctx, yuvFrame); if (ret < 0 && ret != AVERROR_EOF) {av_packet_unref(pkt); continue; }double nowTime = yuvFrame->pts * av_q2d(avStream->time_base); long t = (long) (nowTime * 1000); long time = getCurrentTime() - start_time; long wait = t - time - audio_time; struct timespec abstime = waitTime(wait); pthread_mutex_lock(&video_mutex); pthread_cond_timedwait(&video_cond, &video_mutex,&abstime); pthread_mutex_unlock(&video_mutex); openGLUtils->updateTexture(yuvFrame->width,yuvFrame->height,yuvFrame->data[0],yuvFrame->data[1],yuvFrame->data[2]); openGLUtils->surfaceDraw(); eglUtils->drawEGL(); av_packet_unref(pkt); }av_packet_unref(pkt); }av_frame_free(&yuvFrame); avcodec_close(codec_ctx); avformat_close_input(&fmt_ctx); pthread_cond_destroy(&video_cond); pthread_mutex_destroy(&video_mutex); env->ReleaseStringUTFChars(path_, path); } #define MAX_AUDIO_FRME_SIZE 48000 * 4 extern "C" JNIEXPORT void JNICALL Java_com_example_ffmpegrun_MainActivity_audioPlay(JNIEnv *env, jobject instance, jstring path_) {const char *path = env->GetStringUTFChars(path_, 0); // TODO av_register_all(); AVFormatContext *fmt_ctx = avformat_alloc_context(); if (avformat_open_input(&fmt_ctx, path, NULL, NULL) < 0) {return; }if (avformat_find_stream_info(fmt_ctx, NULL) < 0) {return; }AVStream *avStream = NULL; int audio_stream_index = -1; for (int i = 0; i < fmt_ctx->nb_streams; i++) {if (fmt_ctx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {avStream = fmt_ctx->streams[i]; audio_stream_index = i; break; }}if (audio_stream_index == -1) {return; }AVCodecContext *codec_ctx = avcodec_alloc_context3(NULL); avcodec_parameters_to_context(codec_ctx, avStream->codecpar); AVCodec *avCodec = avcodec_find_decoder(codec_ctx->codec_id); if (avcodec_open2(codec_ctx, avCodec, NULL) < 0) {return; }SwrContext *swr_ctx = swr_alloc(); enum AVSampleFormat in_sample_fmt = codec_ctx->sample_fmt; enum AVSampleFormat out_sample_fmt = AV_SAMPLE_FMT_S16; int in_sample_rate = codec_ctx->sample_rate; int out_sample_rate = in_sample_rate; uint64_t in_ch_layout = codec_ctx->channel_layout; uint64_t out_ch_layout = AV_CH_LAYOUT_STEREO; swr_alloc_set_opts(swr_ctx, out_ch_layout, out_sample_fmt, out_sample_rate, in_ch_layout, in_sample_fmt, in_sample_rate, 0, NULL); swr_init(swr_ctx); int out_channel_nb = av_get_channel_layout_nb_channels(out_ch_layout); jclass player_class = env->GetObjectClass(instance); jmethodID create_audio_track_mid = env->GetMethodID(player_class, "createAudio", "(II)Landroid/media/AudioTrack;"); jobject audio_track = env->CallObjectMethod(instance, create_audio_track_mid, out_sample_rate, out_channel_nb); jclass audio_track_class = env->GetObjectClass(audio_track); jmethodID audio_track_play_mid = env->GetMethodID(audio_track_class, "play", "()V"); jmethodID audio_track_stop_mid = env->GetMethodID(audio_track_class, "stop", "()V"); env->CallVoidMethod(audio_track, audio_track_play_mid); jmethodID audio_track_write_mid = env->GetMethodID(audio_track_class, "write", "([BII)I"); uint8_t *out_buffer = (uint8_t *) av_malloc(MAX_AUDIO_FRME_SIZE); AVPacket *pkt = (AVPacket *) malloc(sizeof(AVPacket)); int ret; while (1) {if (av_read_frame(fmt_ctx, pkt) < 0){av_packet_unref(pkt); break; }ret = avcodec_send_packet(codec_ctx, pkt); if (ret < 0 && ret != AVERROR(EAGAIN) && ret != AVERROR_EOF) {av_packet_unref(pkt); continue; }AVFrame *frame = av_frame_alloc(); ret = avcodec_receive_frame(codec_ctx, frame); if (ret < 0 && ret != AVERROR_EOF) {av_packet_unref(pkt); av_frame_free(&frame); continue; }double nowTime = frame->pts * av_q2d(avStream->time_base); long t = (long) (nowTime * 1000); audio_time = t; start_time = getCurrentTime(); swr_convert(swr_ctx, &out_buffer, MAX_AUDIO_FRME_SIZE, (const uint8_t **) frame->data, frame->nb_samples); int out_buffer_size = av_samples_get_buffer_size(NULL, out_channel_nb, frame->nb_samples, out_sample_fmt, 1); jbyteArray audio_sample_array = env->NewByteArray(out_buffer_size); jbyte *sample_bytep = env->GetByteArrayElements(audio_sample_array, NULL); memcpy(sample_bytep, out_buffer, (size_t) out_buffer_size); env->ReleaseByteArrayElements(audio_sample_array, sample_bytep, 0); env->CallIntMethod(audio_track, audio_track_write_mid, audio_sample_array, 0, out_buffer_size); env->DeleteLocalRef(audio_sample_array); av_frame_free(&frame); av_packet_unref(pkt); }env->CallVoidMethod(audio_track, audio_track_stop_mid); av_free(out_buffer); swr_free(&swr_ctx); avcodec_close(codec_ctx); avformat_close_input(&fmt_ctx); env->ReleaseStringUTFChars(path_, path); }
2017/11/6更新
发现个bug修改一下
声音解码时在av_read_frame()之后加个判断
if(pkt->stream_index == audio_stream_index)
然后再进行播放处理，因为av_read_frame()得到的数据有视频数据和音频数据，因为这个线程是专门处理声音的，所以把视频数据给过滤掉，就像视频线程会过滤音频数据一样
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