AVCodecContex在android中返回零的宽度和高度。

Question

不知道我在下面的代码中犯了什么错误。我正在使用android中的ffmpeg 0.11和SDL2.0。

问：为什么CodecContext的宽度和高度总是为零?..

int main(int argc, char *argv[])
{

    int flags;
    flags = SDL_INIT_VIDEO | SDL_INIT_TIMER;

    if (SDL_Init (flags)) {
        LOGD ("Could not intialize Video for SDL: %s \n", SDL_GetError());
    }
    else 
        LOGD (" SUCCESS: SDL_Init ");

    // ffmpeg Register all services..
    ffmpeg_register_all (); 


    pFrame = avcodec_alloc_frame ();
    context = avformat_alloc_context();

    err = avformat_open_input (&context, "rtsp:ip:port", NULL, NULL);
    if ( err < 0) {
        __android_log_print(ANDROID_LOG_DEBUG, "ffmpegguard", "Unable to open rtsp... ");

        return -1;
    }

    for (i = 0; i < context->nb_streams; i++)
    {               
        // Find the Decoder.
        codec = avcodec_find_decoder(context->streams[i]->codec->codec_id);
        if (codec->type  == AVMEDIA_TYPE_VIDEO ) {
            __android_log_print(ANDROID_LOG_DEBUG, "ffmpegguard", "Found Video Streaming..  ");
            videoStreamIndex = i;

        }
    }

    // Play RTSP
    av_read_play(context);

    // Get Codec Context.
    pCodecCtx = context->streams[videoStreamIndex]->codec;
    if ( pCodecCtx == NULL )
        __android_log_print(ANDROID_LOG_DEBUG, "ffmpegguard", "CodecCtx is NULL>>> ");
    else
        __android_log_print(ANDROID_LOG_DEBUG, "ffmpegguard", "CodecCtx is <<<OK>>> ");


    //Find the Decoder.
    pCodec = avcodec_find_decoder (pCodecCtx->codec_id);
    avcodec_open2 (pCodecCtx, pCodec, NULL);


    int w = pCodecCtx->width;  // Why me getting 0 ? 
    int h = pCodecCtx->height;

    window = SDL_CreateWindow ("Test ffmpeg",SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, w, h, SDL_WINDOW_SHOWN|SDL_WINDOW_ALLOW_HIGHDPI);
    // What this HIGHDPI Means ??

    if ( window != NULL ) 
    {
        LOGD (" WINDOW CREATED.. , create Renderer ..");
        renderer = SDL_CreateRenderer (window, -1, 0);  
    }
    else
    {
        LOGD (" Invalid SDL Window ");  
    }
__android_log_print(ANDROID_LOG_DEBUG, "ffmpegguard", "Width and Height of PCodeccCtx.. %d .. %d " , w, h); 
    return 0;
}

Answer 1

在代码中添加avformat_stream_info()函数，而不是显示高度和宽度