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• FFMPEG - subtitles not showing for the full duration of video

  26 juin 2023, par Caio Maia

  I could not archive the following :

  


  

  1. Have images loaded from a textfile to create a slideshow.

  


  2. Have a background music with volume control.

  


  3. Have my voice.mp3 over the bg music.

  


  4. Have subtitles in the ass format.

  


  5. Have a text shown with drawtext in the full duration of video.

  


  6. in only one command, if possible.

  


  


  The command I tryed is :

  


  ffmpeg.exe -f concat -i images.txt -i bg_music.m4a -i voice.mp3 -filter_complex "[0:v]drawtext=fontfile='fonte.TTF':fontsize=20:fontcolor=white:text='Imagens da internet':x=w-tw-10:y=h-th-10,[0]overlay=10:10,ass=subtitles.txt[out],[1]volume=0.3[a1];[2]volume=2[a2];[a1][a2]amix=inputs=2:duration=shortest[aud]" -map "[out]" -map "[aud]":a -pix_fmt yuv420p -c:v libx264 -c:s mov_text -r 30 -y out.mp4


  


  It works but not for subtitles that are showing only after the first image of th slideshow appears.

  


  the content of images.txt is :

  


  file 'image1.png'
duration 20
file 'image2.png'
duration 5
file 'image3.png'
duration 5


  


  the content of subtitles.txt is

  


  Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:01.00,0:00:06.00,Default,,0,0,0,,Subscribe!
Dialogue: 0,0:00:07.00,0:00:16.00,Default2,,0,0,0,,Like!
Dialogue: 0,0:00:17.00,0:00:26.00,Default,,0,0,0,,Share!


  


  The problem is that only the "Share !" text is shown.

  


• lavc/libopenh264 : Support full range videos in transcoding

  18 avril 2023, par Jun Zhao

  lavc/libopenh264 : Support full range videos in transcoding
  Support full range videos when transcoding, enabled the
  
  YUVJ420P to avoid auto scale from YUVJ420P to YUV420P
  Signed-off-by : Jun Zhao <barryjzhao@tencent.com>
  

  • [DH] libavcodec/libopenh264enc.c

• Capture full-range/lossless rgb frame from capture card that supports NV12 and YUYV output

  13 janvier 2023, par kunal joshi

  I am trying to make a program which captures an image, then i need to compare captured image and the input data which i displayed, both should matc pixel by pixel

  


  Here are the details of my capture card

  


  $ v4l2-ctl —list-formats-ext -d /dev/video0

  


  ioctl: VIDIOC_ENUM_FMT
        Type: Video Capture

        [0]: 'NV12' (Y/CbCr 4:2:0)
                Size: Discrete 3840x2160
                        Interval: Discrete 0.033s (30.000 fps)
                Size: Discrete 2560x1440
                        Interval: Discrete 0.017s (60.000 fps)
                Size: Discrete 1920x1080
                        Interval: Discrete 0.017s (60.000 fps)
                Size: Discrete 1280x720
                        Interval: Discrete 0.017s (60.000 fps)
                Size: Discrete 640x480
                        Interval: Discrete 0.017s (60.000 fps)
        [1]: 'YUYV' (YUYV 4:2:2)
                Size: Discrete 2560x1440
                        Interval: Discrete 0.020s (50.000 fps)
                Size: Discrete 1920x1080
                        Interval: Discrete 0.017s (60.000 fps)
                Size: Discrete 1280x720
                        Interval: Discrete 0.017s (60.000 fps)
                Size: Discrete 640x480
                        Interval: Discrete 0.017s (60.000 fps)
        [2]: '' (30313050-0000-0010-8000-00aa003)
        [3]: '' (e436eb7e-524f-11ce-9f53-0020af0)



  


  $ v4l2-ctl —all

  


  Driver Info:
        Driver name      : uvcvideo
        Card type        : ITE HDMI 4K+ Bridge: ITE HDMI 4
        Bus info         : usb-0000:00:14.0-6
        Driver version   : 5.18.0
        Capabilities     : 0x84a00001
                Video Capture
                Metadata Capture
                Streaming
                Extended Pix Format
                Device Capabilities
        Device Caps      : 0x04200001
                Video Capture
                Streaming
                Extended Pix Format
Priority: 2
Video input : 0 (Camera 1: ok)
Format Video Capture:
        Width/Height      : 1920/1080
        Pixel Format      : 'YUYV' (YUYV 4:2:2)
        Field             : None
        Bytes per Line    : 3840
        Size Image        : 4147200
        Colorspace        : sRGB
        Transfer Function : Rec. 709
        YCbCr/HSV Encoding: Rec. 709
        Quantization      : Default (maps to Limited Range)
        Flags             :
Crop Capability Video Capture:
        Bounds      : Left 0, Top 0, Width 1920, Height 1080
        Default     : Left 0, Top 0, Width 1920, Height 1080
        Pixel Aspect: 1/1
Selection Video Capture: crop_default, Left 0, Top 0, Width 1920, Height 1080, Flags:
Selection Video Capture: crop_bounds, Left 0, Top 0, Width 1920, Height 1080, Flags:
Streaming Parameters Video Capture:
        Capabilities     : timeperframe
        Frames per second: 60.000 (60/1)
        Read buffers     : 0




  


  I have tried using various methods opencv but ffmpeg came the closest

  


  With below command i am able to get good results but not what i want

  


  ffmpeg -y -f v4l2 -pix_fmt NV12 -video_size 1920x1080 -i /dev/video0 -pix_fmt bgra -frames:v 10 webcam%03d.bmp


  


  Reference Image

  


  RGB of Reference image

  


  RGB of captured image

  


  Note :- I am able to capture fine with Aforge on windows, but not with ffmpeg on linux.
Would like to know if anyone has already got solution to this.

  


  Thanks in advance.