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• How to convert FFmpeg command to FFmpeg-Python code ?

  11 mars 2024, par Валентин Арно

  I have this command-line code :

  


  ffmpeg -hide_banner -hwaccel_device auto -hwaccel auto -thread_queue_size 2048 -f dshow -rtbufsize 2048M -pixel_format bgr24 -i video="screen-capture-recorder"  -thread_queue_size 2048 -f dshow -rtbufsize 2048M -channel_layout stereo -i audio="CABLE Output (VB-Audio Virtual Cable)" -filter_complex "[0:v]crop=1920:1040:0:0,scale=in_range=full:out_range=full:eval=init:interl=false:flags=bitexact+accurate_rnd+full_chroma_int,fps=fps=30.000,pp=fa[v1];[1:a]volume=volume=1.2[a1]" -map "[v1]" -map "[a1]" -c:a copy -c:v libx264 -preset ultrafast -tune film  -crf 17 -r 30 -force_key_frames expr:gte(t,n_forced*1) -sc_threshold 0 -pix_fmt yuvj422p -max_muxing_queue_size 2048 -copyts -start_at_zero -y -t 5 "Y:\test\ output_1".mkv


  


  Error : Stream specifier ':a' in filtergraph description ...matches no streams.

  


  And I want to convert it to ffmpeg-python code in Python.

  


  But how can I do it ?

  


  This is what I have done so far :

  


  video_ = ffmpeg.input('video=screen-capture-recorder',
                     thread_queue_size=2048,
                     rtbufsize='2048M',
                     pixel_format='bgr24',
                     framerate=30,
                     f='dshow'
                     )

audio_ = ffmpeg.input('audio=virtual-audio-capturer',
                     thread_queue_size=2048,
                     rtbufsize='2048M',
                     channel_layout='stereo',
                     f='dshow'
                     )
print(' '.join(  
      ffmpeg
      .filter(video_,'fps', fps=30.000)
      .filter(video_,'crop', 1920,1040,0,0)
      .filter(video_,'pp','fa')
      .filter(video_,'scale', in_range='full', out_range ='full', eval='init', interl='false', flags='bitexact+accurate_rnd+full_chroma_int')
      .filter(audio_,'volume',volume=1.2)

      .output('Y:\\test\\output_1.mkv', acodec='copy', vcodec="libx264", preset='ultrafast',
              tune='film', crf=17, r=30, force_key_frames='expr:gte(t,n_forced*1)',
              sc_threshold=0, pix_fmt='yuv420p', max_muxing_queue_size=2048,
              start_at_zero=None, t=15)
      
      .global_args('-hide_banner')
      .global_args('-hwaccel_device', 'auto')
      .global_args('-hwaccel', 'auto')
      .global_args('-report')
      .overwrite_output()
      .compile()
))


  


  Thanks.

  


• ffmpeg mjpeg encoding not recognized by VLC on other device

  25 juin 2023, par Harsh Kumar

  Let me describe the case scenerio first :

  


  I am using RaspberryPi as a USB-UVC gadget to stream a video to a host device connected via USB cable to the Pi .
For this i have a application(may see if you want) which is succesfully streaming the a USB camera live stream using ./uvc-gadget -d /dev/video0 on the Pi side where /dev/video0 is a real USB camera and the rest is just a syntax of application to take the input as some v4l2 capture device.On the Host side i have to just open the VLC and select capture device as the UVC-Camera made by the apllication and play the stream by selcting the MJPG option under the advanced options and only MJPEG format is supported by the application.

  


  So what i thought that is to make a virtual camera device using sudo modprobe v4l2loopback first (/dev/video1 for now ) and then feeding a my Raspberry desktop screen to it using ffmpeg and then feeding this /dev/video1 virtual video capture device to my application as ./uvc-gadget -d /dev/video1.

  


  More graphically,

  


  Desktop screen -> virtual camera -> apllication

  


  But unfortunately i am not getting the desired results given that this service is supported by the appllication (you may refer readme of application) .I get the trival error of 'Your input device can,t be opened ' in VLC when i do the same steps .

  


  Summary ,
I guess i may be doing something wrong for the MJPEG encoding using ffmpeg also ,
Here is the command i am using ,
ffmpeg -probesize 100M -framerate 30 -f x11grab -video_size 1280*720 -i :0.0+0,0 -c:v mjpeg -pix_fmt yuvj422p -f v4l2 /dev/video1.

  


  Also , i checked on raspberry the output of dev/video1 is fine and also tried removing the pix_fmt yuvj422p thinking that it might causing some conflict with color encoding but got the same error.

  


  Will be very thankful if someone can help me figuring out the erorr.
Thanks for your time and patience .

  


• How to rpt stream between two different Laptop [closed]

  19 février 2024, par Faruk

  I want make some test for rtp. I connected Ubuntu Laptop and Windows Laptop with ethernet cable. I want to stream from one computer and run it with VLC from the other.

  


  I did two test for this :

  


  First test(on Ubuntu)

  


  

  1. I streamed with this command : ffmpeg -re -i ~/Videos/test.mp3 -acodec pcm_s16be -ar 44100 -ac 2 -payload_type 10 -f rtp rtp://127.0.0.1:8080

  


  2. I started VLC on Ubuntu and I enter rtp://127.0.0.1:8080 to Open Network Stream

  


  


  This worked.

  


  Second Test

  


  

  1. I connected two Laptops via ethernet cable. Main laptop is Ubuntu and the other one windows.

  


  2. Windows laptop IP address is : 10.42.0.167 (I tested internet and windows laptop can connect to internet)

  


  3. I streamed with this command : ffmpeg -re -i ~/Videos/test.mp3 -acodec pcm_s16be -ar 44100 -ac 2 -payload_type 10 -f rtp rtp://10.42.0.167:8080

  


  4. I checked data on Ubuntu with Wireshark and data is going. I did this test on Windows laptop and data is coming.

  


  5. I started VLC on Windows laptop and I enter rtp://10.42.0.167:8080 to Open Network Stream but VLC can nor play stream audio.

  


  


  What is the reason why the stream can not play on VLC that a Windows laptop even though data is received ?

  


  How can I achieve this ?

  


  Thanks.