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• avformat/smacker : Check for too small pts_inc

  17 janvier 2021, par Michael Niedermayer

  avformat/smacker : Check for too small pts_inc
  Fixes : negation of -2147483648 cannot be represented in type 'int' ; cast to an unsigned type to negate this value to itself
  
  Fixes : 26910/clusterfuzz-testcase-minimized-ffmpeg_dem_SMACKER_fuzzer-6705429132476416
  Found-by : continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavformat/smacker.c

• avcodec/pngdec : Fix paeth prediction with small images

  26 novembre 2014, par Michael Niedermayer

  avcodec/pngdec : Fix paeth prediction with small images
  Fixes out of array read
  
  Fixes : asan_heap-oob_20b0a06_1962_cov_1907976991_delete_node_small.png
  
  Found-by : Mateusz "j00ru" Jurczyk and Gynvael Coldwind
  
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavcodec/pngdec.c

• Stream video from mobile camera to ffmpeg with NDK

  19 juillet 2013, par user2598307

  I need to create an application that captures video from a camera phone and send it to ffmpeg. Everything should be done only NDK level without SDK and Java
   The phone can be Root

  I am trying to open camera on my android device with this function "avformat_open_input()". I give this function a reference to device folder "/dev/msm_camera/" or "/dev/video0".

  I try like this :

        void Java_com_example_camera_MainActivity_testVideo(JNIEnv *env, jclass jc, jstring *filename)
  
  {
  
          av_register_all();
  
          avcodec_register_all();
  
          avformat_network_init();
  
          AVFormatContext* context = avformat_alloc_context();
  
          int video_stream_index,ret,i;
  
          AVInputFormat *input_format = NULL;
  
          const char formatName[] = "mpeg"; //for example mpeg
  
          const jbyte *str;
  
          str = (*env)->GetStringUTFChars(env, filename, NULL); //filename = "/dev/msm_camera"
  
          input_format = av_find_input_format(formatName);
  
          ret = avformat_open_input(&context, str, input_format, NULL);
  
          if (ret < 0){
  
             LOGE("Not open");
  
          }else{
  
             LOGI("camera was open");
  
          }
  
          if(avformat_find_stream_info(context,NULL) < 0){
  
             LOGE("No stream");
  
          }
  
          for(i =0;inb_streams;i++){
  
             if(context->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO)
  
                 video_stream_index = i;
  
          }
  
          AVPacket packet;
  
          AVFrame *pFrame;
  
          av_init_packet(&packet);
  
          pFrame = avcodec_alloc_frame();
  
  
  
                  //open output file
  
          AVOutputFormat* fmt = av_guess_format("avi", NULL, NULL);
  
          AVFormatContext* outputContext = avformat_alloc_context();
  
          outputContext->oformat = fmt;
  
          avio_open2(&outputContext->pb, "/sdcard/test.avi", AVIO_FLAG_WRITE,NULL,NULL);
  
          AVStream* stream=NULL;
  
          AVFrame * frame;
  
          frame = avcodec_alloc_frame();
  
          int cnt = 0, frameDecoded;
  
  
  
                  //start reading packets from stream and write them to file
  
          av_read_play(context);
  
          while(av_read_frame(context,&packet)>=0 && cnt <300){ //Here function return -1
  
            if(packet.stream_index == video_stream_index)
  
            {//packet is video
  
              if(stream == NULL){
  
                 //create stream in file
  
                       stream = avformat_new_stream(outputContext,context->streams[video_stream_index]->codec->codec);
  
                       avcodec_copy_context(stream->codec,context->streams[video_stream_index]->codec);
  
                       stream->sample_aspect_ratio = context->streams[video_stream_index]->codec->sample_aspect_ratio;
  
                       avformat_write_header(outputContext,NULL);
  
               }
  
               packet.stream_index = stream->id;
  
               av_write_frame(outputContext,&packet);
  
               cnt++;
  
             }
  
             av_free_packet(&packet);
  
             av_init_packet(&packet);
  
          }
  
          av_read_pause(context);
  
          av_write_trailer(outputContext);
  
          avio_close(outputContext->pb);
  
          avformat_free_context(outputContext);         
  
   }

  As I know, we cannot get access to camera because my program has not root permission. So how I can give my program root permission ? Or how I can go around this problem ?

  I also tried to interact with the device driver using ioctl commands on C\C++, but I did not succeed because I have no experience and examples in Google.

  Thank you !!!