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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 get the real, actual duration of an MP3 file (VBR or CBR) server-side

  25 septembre 2016, par SquareCat

  I used to calculate the duration of MP3 files server-side using ffmpeg - which seemed to work fine. Today i discovered that some of the calculations were wrong. Somehow, for some reason, ffmpeg will miscalculate the duration and it seems to happen with variable bit rate mp3 files only.

  When testing this locally, i noticed that ffmpeg printed two extra lines in green.

  Command used :

  ffmpeg -i song_9747c077aef8.mp3

  ffmpeg says :

  [mp3 @ 0x102052600] max_analyze_duration 5000000 reached at 5015510
  
  [mp3 @ 0x102052600] Estimating duration from bitrate, this may be inaccurate

  After a nice, warm google session, i discovered some posts on this, but no solution was found.

  I then tried to increase the maximum duration :

  ffmpeg -analyzeduration 999999999 -i song_9747c077aef8.mp3

  After this, ffmpeg returned only the second line :

  [mp3 @ 0x102052600] Estimating duration from bitrate, this may be inaccurate

  But in either case, the calculated duration was just plain wrong. Comparing it to VLC i noticed that there the duration is correct.

  After more research i stumbled over mp3info - which i installed and used.

  mp3info -p "%S" song_9747c077aef8.mp3

  mp3info then returned the CORRECT duration, but only as an integer, which i cannot use as i need a more accurate number here. The reason for this was explained in a comment below, by user blahdiblah - mp3info is simply pulling ID3 info from the file and not actually performing any calculations.

  I also tried using mplayer to retrieve the duration, but just as ffmpeg, mplayer is returning the wrong value.

• System command - doesn't get return

  28 novembre 2011, par waxical

  Seem to have a problem with PHP system command - I place a command with it and if return code is above 0 - I cite failure otherwise I carry on.

  It never seems to return on FFMPEG commands lower than a certain number of seconds (generally 3-5 seconds duration video encodes that are very quick to encode). Is this something that'd be from FFMPEG not returning properly or system command ?

  An example command :-

  system('ffmpeg -i /home/test.wmv -f flv 340x160 -vcodec libx264 export.flv', $returnCode);
  
  if($returnCode > 0) { error(); }

  The only way to get round this seems to be to run a timer and check log files if nothing back after an amount of time but if anyone has any pointers - be gratefully received.