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• FFMPEG : How to add transparency to watermark logo ? Getting error : "Filter scale2ref has an unconnected output"

  12 septembre 2023, par Danny

  Hey guys I am new to Ffmpeg, I want to resize a watermark logo according to the video size and add transparency to it. The code I have is not working as expected.

  


  This is the code

  


  ffmpeg -i $initialFilePath -i $assetLogoFilePath -y -filter_complex '[1][0]scale2ref=w=oh*mdar:h=ih*0.03[logo][video];[1]format=rgba,colorchannelmixer=aa=0.5[logo];[video][logo]overlay=W-w-5:H-h-5' -c:a copy $temporaryDirectoryPath/$finalVideoPath"


  


  I am getting this error Filter scale2ref has an unconnected output.

  


  Please do help. Thanks

  


• Trying to fix VPlayer's seeking ability, need some guidance [Android FFmpeg]

  1er juin 2016, par vxh.viet

  I’m trying to fix the currently broken seeking ability of VPlayer which is a FFmpeg player for Android. Being a Java developer, C code looks like alien language to me so can only fix it using common logic (which could make any C veteran have a good laugh).

  The relevant file is player.c and I’ll try my best to point out the relevant modification.

  So the basic idea is because FFmpeg’s av_seek_frame is very inaccurate even with AVSEEK_FLAG_ANY so I’m trying to follow this suggestion to seek backward to the nearest keyframe and then decode to the frame I want. One addition note is since I want to seek based on millisecond while the said solution show the way to seek by frame which is potentially a source of problem.

  In the Player I add the following fields :

  struct Player{
  
  ....
  
  AVFrame *frame;
  
  int64_t current_time_stamp;
  
  }; 

  In the player_read_from_stream I modify the seeking part as :

  void * player_read_from_stream(void *data) {
  
      ...
  
      struct DecoderData *decoder_data = data;
  
      int stream_no = decoder_data->stream_no;
  
      AVCodecContext * ctx = player->input_codec_ctxs[stream_no];
  
      ...
  
      // seeking, start my stuff
  
      if(av_seek_frame(player->input_format_ctx, seek_input_stream_number, seek_target, AVSEEK_FLAG_BACKWARD) >= 0){
  
          //seek to key frame success, now need to read every frame from the key frame to our target time stamp
  
  
  
  
  
          while(player->current_time_stamp < seek_target){
  
  
  
              int frame_done;
  
  
  
              while (av_read_frame(player->input_format_ctx, &packet) >= 0) {
  
                  if (packet.stream_index == seek_input_stream_number) {
  
  
  
                      avcodec_decode_video2(ctx, player->frame, &frame_done, &packet);
  
                      LOGI(1,"testing_stuff ctx %d", *ctx);
  
                      if (frame_done) {
  
  
  
                          player->current_time_stamp = packet.dts;
  
                          LOGI(1,"testing_stuff current_time_stamp: %"PRId64, player->current_time_stamp);
  
                          av_free_packet(&packet);
  
                          return;
  
                      }
  
                  }
  
                  av_free_packet(&packet);
  
              }
  
          }
  
  
  
  
  
      }
  
      //end my stuff
  
  
  
      LOGI(3, "player_read_from_stream seeking success");
  
  
  
      int64_t current_time = av_gettime();
  
      player->start_time = current_time - player->seek_position;
  
      player->pause_time = current_time;        
  
  }

  And in player_alloc_frames I allocate the memory for my frame as :

  int player_alloc_frames(struct Player *player) {
  
      int capture_streams_no = player->caputre_streams_no;
  
      int stream_no;
  
      for (stream_no = 0; stream_no < capture_streams_no; ++stream_no) {
  
          player->input_frames[stream_no] = av_frame_alloc();
  
  
  
          //todo: test my stuff
  
          player->frame = av_frame_alloc();
  
          //end test
  
  
  
          if (player->input_frames[stream_no] == NULL) {
  
              return -ERROR_COULD_NOT_ALLOC_FRAME;
  
          }
  
      }
  
      return 0;
  
  }

  Currently it just keep crashing and being a typical Android NDK’s "feature", it just provide a super helpful stack trace :

  libc: Fatal signal 11 (SIGSEGV), code 1, fault addr 0x40 in tid 2717 (FFmpegReadFromS)

  I very much appreciate if anyone could help me solve this problem. Thank you for your time.

• arm : Check for the .arch directive in configure

  3 mai 2017, par Martin Storsjö

  arm : Check for the .arch directive in configure
  When targeting windows, the .arch directive isn’t available.
  So far, when building for windows, we’ve always used gas-preprocessor,
  
  both when using msvc’s armasm and when using clang. Lately, clang/llvm
  
  has implemented the last missing piece (altmacro support) for building
  
  our assembly without gas-preprocessor. This means that we now build
  
  for arm/windows with clang without any extra compatibility layer.
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DBH] configure
  • [DBH] libavutil/arm/asm.S