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• av_read_frame function in ffmpeg in android always returning packet.stream_index as 0

  31 juillet 2013, par droidmad

  I am using the following standard code pasted below (ref : http://dranger.com/ffmpeg/) to use ffmpeg in android using ndk. My code is working fine in ubuntu 10.04 using gcc compiler. But I am facing an issue in android.The issue is av_read_frame(pFormatCtx, &packet) is always returning packet.stream_index=0. I have tested my code with various rtsp urls and I have the same behaviour in all cases. I do not have any linking or compiling issues as everything seems to be working fine except this issue. I am trying to solve this from last 2 days but I am stuck badly.Please point me in right direction.

  #include 
  
  #include <android></android>log.h>
  
  
  
  #include <libavcodec></libavcodec>avcodec.h>
  
  #include <libavformat></libavformat>avformat.h>
  
  #include <libswscale></libswscale>swscale.h>
  
  
  
  #include 
  
  #define DEBUG_TAG "mydebug_ndk"
  
  
  
  jint Java_com_example_tut2_MainActivity_myfunc(JNIEnv * env, jobject this,jstring myjurl) {
  
    AVFormatContext *pFormatCtx = NULL;
  
    int             i, videoStream;
  
    AVCodecContext  *pCodecCtx = NULL;
  
    AVCodec         *pCodec = NULL;
  
    AVFrame         *pFrame = NULL;
  
    AVPacket        packet;
  
    int             frameFinished;
  
  
  
    AVDictionary    *optionsDict = NULL;
  
    struct SwsContext *sws_ctx = NULL;
  
  
  
    jboolean isCopy;
  
    const char * mycurl = (*env)->GetStringUTFChars(env, myjurl, &amp;isCopy);
  
    __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG, "NDK:p2: [%s]", mycurl);
  
  
  
    // Register all formats and codecs
  
    av_register_all();
  
    avformat_network_init();
  
    // Open video file
  
    __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG, "NDK:before_open");
  
  
  
    if(avformat_open_input(&amp;pFormatCtx, mycurl, NULL, NULL)!=0)
  
        return -1;
  
    __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG, "start: %d\t%d\n",pFormatCtx->raw_packet_buffer_remaining_size,pFormatCtx->max_index_size);
  
  
  
    (*env)->ReleaseStringUTFChars(env, myjurl, mycurl);
  
    __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG, "NDK:before_stream");
  
    // Retrieve stream information
  
    if(avformat_find_stream_info(pFormatCtx, NULL)&lt;0)
  
        return -1;
  
    __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG, "NDK:after_stream");
  
    // Find the first video stream
  
    videoStream=-1;
  
    for(i=0; inb_streams; i++)
  
        if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO) {
  
          videoStream=i;
  
          break;
  
        }
  
    if(videoStream==-1)
  
        return -1; // Didn&#39;t find a video stream
  
    __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG, "NDK:after_videostream");
  
    // Get a pointer to the codec context for the video stream
  
    pCodecCtx=pFormatCtx->streams[videoStream]->codec;
  
    __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG, "NDK:after_codec_context");
  
  
  
    // Find the decoder for the video stream
  
    pCodec=avcodec_find_decoder(pCodecCtx->codec_id);
  
    __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG, "NDK:after_decoder");
  
  
  
    if(pCodec==NULL)
  
        return -1;
  
    __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG, "NDK:found_decoder");
  
  
  
    // Open codec
  
    if(avcodec_open2(pCodecCtx, pCodec, &amp;optionsDict)&lt;0)
  
        return -1;
  
    // Allocate video frame
  
    pFrame=avcodec_alloc_frame();
  
    sws_ctx = sws_getContext(pCodecCtx->width,pCodecCtx->height,pCodecCtx->pix_fmt,pCodecCtx->width,
  
          pCodecCtx->height,PIX_FMT_YUV420P,SWS_BILINEAR,NULL,NULL,NULL);
  
    __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG, "NDK:before_while");
  
  
  
    int count=0;
  
    while(av_read_frame(pFormatCtx, &amp;packet)>=0) {
  
          __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG, "entered while: %d   %d   %d\n", packet.duration,packet.stream_index,packet.size);
  
  
  
        if(packet.stream_index==videoStream) {
  
            // Decode video frame
  
            //break;
  
            avcodec_decode_video2(pCodecCtx, pFrame, &amp;frameFinished,&amp;packet);
  
            __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG, "NDK:in_while");
  
            if(frameFinished) {
  
                __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG, "NDK:gng_out_of_while");
  
                  break;
  
            }
  
        }
  
  
  
        // Free the packet that was allocated by av_read_frame
  
        av_free_packet(&amp;packet);
  
        if(++count>1000)
  
           return -2; //infinite while loop
  
    }
  
    __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG, "NDK:after_while");
  
  
  
    // Free the YUV frame
  
    av_free(pFrame);
  
    // Close the codec
  
    avcodec_close(pCodecCtx);
  
    // Close the video file
  
    avformat_close_input(&amp;pFormatCtx);
  
  
  
    return 0;
  
  
  
  }

• How to execute a cmd command using java program [duplicate]

  21 mars 2013, par Yaswanth Veeramachaneni

  This question already has an answer here :

  • How to run Unix shell script from java code ?
    

    9 answers

  I want to execute a cmd command using java program

  ffmpeg -i input.mp4 output.mp3

  I want the above command to be executed in cmd using java language.
  and in above code I have directly given the input file name to execute but can I write a code so that user can manually give an input file ?

• Parsing avconv/ffmpeg rawvideo output ?

  23 avril 2013, par DigitalMan

  I'm about to begin a project that will involve working with the output of avconv/ffmpeg, pixel-by-pixel, in rgb32 format. I intend to work with a raw byte stream, such as from the pipe protocol. Basic pointer arithmetic (C/C++) will be used to iterate over these pixels, and modify them in arbitrary manners in real-time.

  I've created a very small file using rawvideo format and codec, and opened it up in a hex editor. As expected, it's just a series of pixels, read right to left, top to bottom. No distinguishing between lines - no problem, if you know how wide the video is beforehand. No distinguishing between frames - no problem, if you also know how tall the video is. No file header for frame rate, or even what the encoding (rgb32, rgb24, yuv, etc.) is - again, as long as you already know, it can be worked with.

  The problem occurs when - for one reason or another - some bytes are missing. Maybe the stream isn't being examined from the beginning, which is likely be the case in my project, or maybe something just got lost. All the pre-existing knowledge in the world (besides maybe a byte count of what's been missed, not gonna happen) won't prevent it from happily chugging along, with an incorrect offset of line and frame.

  So, what I'm looking for is an option for rawvideo, or possibly some other format/codec, that will allow me to work with the resulting stream at the pixel level, in RGB, yet still have a clear definition of where a new frame begins, even if it happens to start "looking" in the middle of a frame. (Width, height, and framerate will indeed be known.)