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• ffmpeg audio output in iOS

  19 septembre 2015, par user3249421

  Good day,

  I have own project which using iFrameExtraktor (https://github.com/lajos/iFrameExtractor). I modified initWithVideo method to :

  -(id)initWithVideo:(NSString *)moviePath imgView: (UIImageView *)imgView {
  
  if (!(self=[super init])) return nil;
  
  
  
  AVCodec         *pCodec;
  
  AVCodec         *aCodec;
  
  
  
  // Register all formats and codecs
  
  avcodec_register_all();
  
  av_register_all();
  
  
  
  imageView = imgView;
  
  
  
  // Open video file
  
  if(avformat_open_input(&pFormatCtx, [moviePath cStringUsingEncoding:NSASCIIStringEncoding], NULL, NULL) != 0) {
  
      av_log(NULL, AV_LOG_ERROR, "Couldn't open file\n");
  
      goto initError;
  
  }
  
  
  
  // Retrieve stream information
  
  if(avformat_find_stream_info(pFormatCtx,NULL) < 0) {
  
      av_log(NULL, AV_LOG_ERROR, "Couldn't find stream information\n");
  
      goto initError;
  
  }
  
  
  
  // Find the first video stream
  
  if ((videoStream =  av_find_best_stream(pFormatCtx, AVMEDIA_TYPE_VIDEO, -1, -1, &pCodec, 0)) < 0) {
  
      av_log(NULL, AV_LOG_ERROR, "Cannot find a video stream in the input file\n");
  
      goto initError;
  
  }
  
  
  
  if((audioStream = av_find_best_stream(pFormatCtx, AVMEDIA_TYPE_AUDIO, -1, -1, &aCodec, 0)) < 0 ){
  
      av_log(NULL, AV_LOG_ERROR, "Cannot find a audio stream in the input file\n");
  
      goto initError;
  
  }
  
  
  
  // Get a pointer to the codec context for the video stream
  
  pCodecCtx = pFormatCtx->streams[videoStream]->codec;
  
  aCodecCtx = pFormatCtx->streams[audioStream]->codec;
  
  
  
  // Find the decoder for the video stream
  
  pCodec = avcodec_find_decoder(pCodecCtx->codec_id);
  
  if(pCodec == NULL) {
  
      av_log(NULL, AV_LOG_ERROR, "Unsupported video codec!\n");
  
      goto initError;
  
  }
  
  
  
  aCodec = avcodec_find_decoder(aCodecCtx->codec_id);
  
  if(aCodec == NULL) {
  
      av_log(NULL, AV_LOG_ERROR, "Unsupported audio codec!\n");
  
      goto initError;
  
  }
  
  
  
  // Open codec
  
  if(avcodec_open2(pCodecCtx, pCodec, NULL) < 0) {
  
      av_log(NULL, AV_LOG_ERROR, "Cannot open video decoder\n");
  
      goto initError;
  
  }
  
  
  
  if(avcodec_open2(aCodecCtx, aCodec, NULL) < 0){
  
      av_log(NULL, AV_LOG_ERROR, "Cannot open audio decoder\n");
  
      goto initError;
  
  }
  
  
  
  // Allocate video frame
  
  pFrame = av_frame_alloc();
  
  
  
  outputWidth = pCodecCtx->width;
  
  self.outputHeight = pCodecCtx->height;
  
  
  
  lastFrameTime = -1;
  
  [self seekTime:0.0];
  
  
  
  return self;
  
  
  
  initError:
  
      //[self release];
  
      return nil;
  
  }

  Video rendering works fine, but I don’t know how play audio to device output.

  Thanks for any tips.

• Displaying 450 image files from SDCard at 30fps on android

  11 décembre 2013, par nikhilkerala

  I am trying to develop an app that takes a 15 seconds of video, allows the user to apply different filters, shows the preview of the effect, then allows to save the processed video to sdcard. I use ffmpeg to split the video into JPEG frames, apply the desired filter using GPUImage to all the frames, then use ffmpeg to encode the frames back to a video. Everything works fine except the part where user selects the filter. When user selects a filter, the app is supposed to display the preview of the video with the filter applied. Though 450 frames get the filter applied fairly quick, displaying the images sequentially at 30 fps (to make the user feel the video is being played) is performing poorly. I tried different approaches but the maximum frame rate I could attain even on the fastest devices is 10 to 12 fps.

  The AnimationDrawable technique doesn't work in this case because it requires the entire images to be buffered into memory which in this case is huge. App crashes.

  The below code is the best performing one so far (10 to 12 fps).

  package com.example.animseqvideo;
  
  import ......
  
  
  
  public class MainActivity extends Activity {
  
      Handler handler;
  
      Runnable runnable;
  
      final int interval = 33; // 30.30 FPS
  
      ImageView myImage;
  
      int i=0;
  
  
  
      @Override
  
      protected void onCreate(Bundle savedInstanceState) {
  
          super.onCreate(savedInstanceState);
  
          setContentView(R.layout.activity_main);
  
  
  
          myImage = (ImageView) findViewById(R.id.imageView1);
  
  
  
          handler = new Handler();
  
          runnable = new Runnable(){
  
              public void run() {
  
  
  
                  i++;  if(i>450)i=1;
  
  
  
                  File imgFile = new  File(Environment.getExternalStorageDirectory().getPath() + "/com.example.animseqvideo/image"+ String.format("%03d", i)   +".jpg");
  
                  if(imgFile.exists()){
  
                      Bitmap myBitmap = BitmapFactory.decodeFile(imgFile.getAbsolutePath());
  
                      myImage.setImageBitmap(myBitmap);
  
                  }
  
  //SOLUTION EDIT - MOVE THE BELOW LINE OF CODE AS THE FIRST LINE OF run() AND FPS=30 !!!
  
  
  
                  handler.postDelayed(runnable, interval);
  
              }
  
          };
  
          handler.postAtTime(runnable, System.currentTimeMillis()+interval);
  
          handler.postDelayed(runnable, interval);
  
      }
  
  }

  I understand that the process of getting an image from SDCard, decoding it, then displaying it onto the screen involves the performance of the SDCard reading, the CPUs performance and graphics performance of the device. But I am wondering if there is a way I could save a few milliseconds in each iteration. Any suggestion would be of great help at this point.

• ffmpeg build from source fails in docker container ?

  24 mars 2016, par John Allard

  I’m trying to make some changes to the ffmpeg source code (yes, I’m a masochist), and to start I booted an Arch Linux docker container, installed the requirements, downloaded ffmpeg source code, and tried to compile, but I’m getting some extremely odd errors.

  compile command :

  ./configure --bindidr=~/ffmpeg_build --enable-gpl --enable-libass --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis --enable-libx264 --enable-nonfree

  Output :

  ./configure:unset:3338: no such has table element: mktemp
  
  pr: /tmp/ffconf.uQI7CeV.c: No such file or directory.
  
  pr: /tmp/ffconf.uQI7CeV.c: No such file or directory.
  
  pr: /tmp/ffconf.uQI7CeV.c: No such file or directory.
  
  pr: /tmp/ffconf.uQI7CeV.c: No such file or directory.
  
  ... (24 times)
  
  pr: /tmp/ffconf.uQI7CeV.c: No such file or directory.
  
  pr: /tmp/ffconf.r547UgWy.m: No such file or directory.
  
  ./configure:53378: parse error near '}'
  
  ==> ERROR" A failure occured in build()
  
      Aborting...
  
  The build failed.

  This doesn’t seem to be a problem with ffmpeg, more a problem with the container. If I check find /tmp -name ffconf\* I see that the files do exist and they contain

  extern int getrusage();
  
  int main(void){ getrusage(); }

  what in the hell is going on ? hash tabled ? mktemp not working ? files not being found ?

  edit-

  here is what is on the line numbers in the files that give the errors

  3338:configure - unset -f mktemp
  
  5338:configure - check_builtin gmtime_r time.g "time_t * time; strict tm*; gmtime_r(time, tm)"

  edit2 - Here’s the dockerfile (cloned from here https://hub.docker.com/r/greyltc/archlinux/ /dockerfile/)

  # Arch Linux baseline docker container
  
  # Generated on Sat Mar 19 14:26:28 GMT 2016 using code in this GitHub repo:
  
  # https://github.com/greyltc/docker-archlinux
  
  FROM scratch
  
  MAINTAINER Grey Christoforo <grey@christoforo.net>
  
  
  
  # copy in super minimal root filesystem archive
  
  ADD archlinux.tar.xz /
  
  
  
  # perform initial container setup tasks
  
  RUN setup-arch-docker-container
  
  
  
  # this allows the system profile to be sourced at every shell
  
  ENV ENV /etc/profile