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• How to decode Byte string from continous video frames in python

  15 juillet 2021, par fresch man

  i am trying to get PNG from a video stream. first i connect the server during socket, and i recieve presistent byte string. however when i use Pickel ,i get a Error,that is UnpicklingError : invalid load key, '\x10.

  


  i surpose that ,if i should first do someting to the bytestring before i use pickel.or i should use another methode

  


  i have already search in the internet, but all the answers are , open locally video and so ..but my byte string are acctully presistent RAW video frames(yuv420) during tcp transport.

  


  `import socket,os,struct,numpy,pickle
TCP_IP = '192.168.0.90'
TCP_PORT = 5000
BUFFER_SIZE =1024
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((TCP_IP, TCP_PORT))
while True :
        data = s.recv(BUFFER_SIZE)
        data = pickle.loads(data) `


  


  thank you

  


• ffmpeg sequence of multiple filters syntax

  5 juillet 2021, par otomari

  i am trying to use multiple filters in ffpmeg, but it does not allow more than one -af.
so, then i decided to try to do it with a -complex_filter.

  


  sudo ffmpeg -f alsa -i default:CARD=Device \
  -filter_complex \
  "lowpass=5000,highpass=200; \
   volume=+5dB; \
   afftdn=nr=0.01:nt=w;" \
  -c:a libmp3lame -b:a 128k -ar 48000 -ac 1 -t 00:00:05 -y $recdir/audio_$(date '+%Y_%m_%d_%H_%M_%S').mp3


  


  it must work, but for some reason i get an error :

  


  Guessed Channel Layout for Input Stream #0.0 : stereo
Input #0, alsa, from 'default:CARD=Device':
  Duration: N/A, start: 1625496748.441207, bitrate: 1536 kb/s
  Stream #0:0: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
[AVFilterGraph @ 0xaaab0a8b14e0] No such filter: ''
Error initializing complex filters.
Invalid argument


  


  i have tried quotes and others, nothing helps..

  


• How to manipulate a Uri as File in android

  3 juin 2021, par Omid.N

  I am trying to use FFmpeg in android. As you know the framework no longer lets you to use absolute paths or open files freely even with WRITE_EXTERNAL_STORAGE permission :|
  
So, using the SAF, I get the file as an Uri, then I need to put it as an argument to ffmpeg to encode it but it only accepts file paths.

  


  How can i achieve this ?
  

  


  Note : There are some bad practices in my code but I hope we can ignore them for now because that's not the problem here :)

  


  public class MainActivity extends AppCompatActivity {

    private static final int PICK_VIDEO_FILE = 2;

    private static final String TAG = "MainActivity";
    
    File theFile;
    TextView textView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {


        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        textView = (TextView) findViewById(R.id.text_view);

        
        if (theFile == null) {
            openFile(Uri.fromFile(new File("/storage/emulated/0/")));
        }


    }

    @Override
    protected void onResume() {
        super.onResume();
        if (theFile !=null) {

            FFmpegSession fFmpegSession = FFmpegKit.executeAsync("-i " + theFile.getAbsolutePath()
                            + " -c:v mpeg4 file:///storage/emulated/0/out.mp4",
                    new ExecuteCallback() {
                        @Override
                        public void apply(Session session) {

                        }
                    });
            try {
                Thread.sleep(5000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            textView.setText("" + fFmpegSession.getState().name() + "    " + fFmpegSession.getOutput());
        }
    }

    private void openFile(Uri pickerInitialUri) {
        Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
        intent.addCategory(Intent.CATEGORY_OPENABLE);
        intent.setType("video/mp4");
        
        // Optionally, specify a URI for the file that should appear in the
        // system file picker when it loads.
        intent.putExtra(DocumentsContract.EXTRA_INITIAL_URI, pickerInitialUri);

        startActivityForResult(intent, PICK_VIDEO_FILE);
    }
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {

        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == PICK_VIDEO_FILE) {
            if (resultCode == RESULT_OK) {
                theFile = new File(data.getData().getPath());
            }
        }

    }