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• Bash : Create copy of music files in different format and folder

  13 mai 2021, par Brett Sjoholm

  I'm trying to create a bash scipt to simply automate finding my flac files and creating an alac copy of them in a separate folder. Just so I have my little itunes folder. Want to automate because so many.

  


  So I find my flac folders within my Eminem folder....

  


  :~$ find /mnt/music/Eminem -type d -name *FLAC
    /mnt/music/Eminem/2009 Relapse FLAC
    /mnt/music/Eminem/1996 Infinite FLAC
    /mnt/music/Eminem/1999 The Slim Shady LP FLAC
    /mnt/music/Eminem/2000 Marshall Mathers LP FLAC


  


  Now instead of going into each folder and converting manually using something like

  


      ffmpeg -i track.flac -acodec alac track.m4a...


  


  How do I, within a bash script, take these multiple folders. Create an ALAC copy of the contents in /mnt/music/iTunes using FFMpeg ?

  


  New folder will be...

  


  /mnt/music/iTunes/Eminem/2009 Relapse ALAC/track.m4a


  


  All flac folders have FLAC at the end in the same folder structure.

  


  /mnt/music/Artist/Year Album FLAC


  


  I understand most of the locating, copying, converting, manually terminal command stuff but when it comes to putting it into a bash script. I don't understand how I take the output of each command and use it for another. The list of folder for example. Don't know how to automate doing all the steps for each.

  


  Kind of long winded but any help will be much appreciated. Even some videos you recommend for learning.

  


• Not able to display first frame of mp4 file

  23 juin 2024, par Jatin Parmar

  I am learning OpenCV from YouTube, and I just created a very basic program in Python.

  


  import cv2 as cv

sources = cv.VideoCapture("test.mp4");

if not sources.isOpened():
    print("Failed to open video file");
else:
    print("video file opened successfully");

win_name = "test"
cv.namedWindow(win_name)

(has_input, frame) = sources.read()
if has_input:
    cv.imshow(win_name, frame[...,::-1])
    cv.waitKey(0)

sources.release()


  


  But when I run the program, I have the following errors : I have tried Googling it, but I didn't find any working solutions.

  


  [av1 @ 0x55e6dc8b0780] Missing Sequence Header.
[av1 @ 0x55e6dc8b0780] Missing Sequence Header.
[av1 @ 0x55e6dc8b0780] Missing Sequence Header.
[av1 @ 0x55e6dc8b0780] Missing Sequence Header.
[av1 @ 0x55e6dc8b0780] Missing Sequence Header.
[av1 @ 0x55e6dc8b0780] Missing Sequence Header.
[av1 @ 0x55e6dc8b0780] Missing Sequence Header.
[av1 @ 0x55e6dc8b0780] Missing Sequence Header.
[av1 @ 0x55e6dc8b0780] Missing Sequence Header.
video file opened successfully
[av1 @ 0x55e6dc97a7c0] Your platform doesn't suppport hardware accelerated AV1 decoding.
[av1 @ 0x55e6dc97a7c0] Failed to get pixel format.


  


  here is the link of video
https://drive.google.com/file/d/1TgY5O6pFLU3eEGsvmU0LoAw6_I8kGM6s/view?usp=sharing
I have no idea how to fix this.

  


• How to decode frames from MDAT atom extracted from mp4 video [closed]

  24 septembre 2024, par Gurinderbeer Singh

  I am new to video codecs and learning video file format specifications. I have read about QUICKTIME file format specifications from here, and MP4 file format (which is almost similar) from here. There are atoms such FTYPE, MOOV, MDAT etc. The MDAT atom contains actual audio and video data. The MOOV atom contains information about how to extract data from MDAT, it gives references to chunks (samples).

  



  I want to extract the video samples in MDAT atom from video file without using any tool such ffmpeg, or juggler etc. I can write my own code for this. The problem is, even if I can locate the video data (samples) in MDAT by using information from MOOV, these samples are compressed. And we need to uncompress these to get frames.
My question is can we uncompress the samples extracted from MDAT and get the actual video frames ?

  



  Tools such as xuggler, ffmpeg etc are used to extract frames from video files. 
But here I want to extract the samples(for video data) from MDAT by writing my own code, but then I want to uncompress those by using some tool. I don't want to write codecs.

  



  Can anyone please help me with this....!

  



  Thanks...