android - 在 Android 中使用 ffmpeg 读取 RTSP 流时 15 秒后出现 Segfault

Question

我正在尝试通过 javacv 使用 ffmpeg 读取 RTSP 流.在对 sws_scale 的调用出现段错误之前，我可以查看拳头 15 秒左右。这是否意味着我的内存不足？如果是这样，知道我做错了什么吗？

    av_register_all();
    avcodec.avcodec_register_all();
    avformat_network_init();
    AVFormatContext avFormatContext = avformat.avformat_alloc_context();

    if(0 != avformat_open_input(avFormatContext, "rtsp://192.168.0.107:7654/lov2.ffm", null, null)){
        throw new RuntimeException("avformat_open_input failed");
    }

    if(avformat_find_stream_info(avFormatContext, null) < 0){
        throw new RuntimeException("avformat_find_stream_info failed");
    }

    int video_stream_index = 0;

    //search video stream
    for(int i = 0; i < avFormatContext.nb_streams(); i++){
        if(avFormatContext.streams(i).codec().codec_type() == AVMEDIA_TYPE_VIDEO){
            video_stream_index = i;
        }
    }
    Log.d(TAG, "checkpoint 3");
    AVPacket packet = new AVPacket();
    av_init_packet(packet);

    AVStream stream = new AVStream();
    int cnt = 0;

    //start reading packets from stream and write them to file
    av_read_play(avFormatContext);//play RTSP
    AVCodecContext avCodecContext = avFormatContext.streams(video_stream_index).codec();
    AVCodec codec = avcodec_find_decoder(avCodecContext.codec_id());

    if (codec == null){
        throw new RuntimeException("codec not found");
    }

    if (avcodec_open2(avCodecContext, codec, null) < 0){
        throw new RuntimeException("could not open codec");
    }

    SwsContext img_convert_ctx = new SwsContext();
    img_convert_ctx = swscale.sws_getCachedContext(
            img_convert_ctx,
            avCodecContext.width(), avCodecContext.height(), 
            avCodecContext.pix_fmt(), avCodecContext.width(), avCodecContext.height(),
            PIX_FMT_RGB24, SWS_BICUBIC, null, null, null
    );

    int size = avpicture_get_size(PIX_FMT_YUV420P, avCodecContext.width(), avCodecContext.height());
    BytePointer picture_buf = new BytePointer(av_malloc(size));
    AVFrame frame = avcodec_alloc_frame();
    AVFrame picrgb = avcodec_alloc_frame();

    int size2 = avpicture_get_size(avutil.PIX_FMT_RGB24, avCodecContext.width(), avCodecContext.height());
    BytePointer picture_buf2 = new BytePointer(av_malloc(size2));

    avpicture_fill(frame, picture_buf, PIX_FMT_YUV420P, avCodecContext.width(), avCodecContext.height());
    avpicture_fill(picrgb, picture_buf2, avutil.PIX_FMT_RGB24, avCodecContext.width(), avCodecContext.height());
    Log.d(TAG, String.format("h: %d,  w: %d; h: %d w: %d", avCodecContext.width(), avCodecContext.height(), avCodecContext.height(), frame.width()));
    Log.d(TAG, "checkpoint 6");
    Bitmap bmp = Bitmap.createBitmap(avCodecContext.width(), avCodecContext.height(), Bitmap.Config.RGB_565);
    while(av_read_frame(avFormatContext, packet) >= 0){

        if(packet.size() > 0 && packet.stream_index() == video_stream_index){//packet is video
            int[] gotFrame = new int[]{0};
            int len = avcodec_decode_video2(avCodecContext, frame, gotFrame, packet);
            if(gotFrame[0] > 0){
                swscale.sws_scale(
                        img_convert_ctx, 
                        frame.data(0), frame.linesize(), 
                        0, avCodecContext.height(), 
                        picrgb.data(0), picrgb.linesize());
                bmp.copyPixelsFromBuffer(picture_buf2.asByteBuffer());
                videoView.drawFrame(bmp);
            }
        }
        av_free_packet(packet);
        av_init_packet(packet);
    }
    av_free(frame);
    av_free(picrgb);
    av_free(picture_buf);
    av_free(picture_buf2);

    av_read_pause(avFormatContext);

堆栈跟踪:

 F/libc    ( 7460): Fatal signal 11 (SIGSEGV) at 0x76100005 (code=1), thread 7474 (Thread-13601)
E/Sensors (  720): accelHandler 0.201182 0.180824 10.950029
I/DEBUG   ( 6409): *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
I/DEBUG   ( 6409): Build fingerprint: 'Verizon/d2vzw/d2vzw:4.1.2/JZO54K/I535VRBMB1:user/release-keys'
I/DEBUG   ( 6409): pid: 7460, tid: 7474, name: Thread-13601  >>> com.example.javacv.stream.test2 <<<
I/DEBUG   ( 6409): signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 76100005
I/DEBUG   ( 6409):     r0 57995360  r1 594f3c30  r2 59349200  r3 59349020
I/DEBUG   ( 6409):     r4 59349020  r5 76100005  r6 00000060  r7 594f3cf0
I/DEBUG   ( 6409):     r8 59349200  r9 59349020  sl 000001e0  fp 76100005
I/DEBUG   ( 6409):     ip 594f3cf0  sp 5e08bb08  lr 59308bec  pc 593103b8  cpsr 00000010

常问问题:

为什么不使用媒体播放器？

MediaPlayer 在流上强制延迟约 2 秒，我真的需要 <100 毫秒。

Answer 1

我对 sws_scale 使用了错误的参数。本来应该:

swscale.sws_scale(
    img_convert_ctx, 
    new PointerPointer(frame), frame.linesize(), 
    0, avCodecContext.height(), 
    new PointerPointer(picrgb), picrgb.linesize());