Recherche avancée

Sur d’autres sites (7823)

• ffmpeg is overlying images when making movie from png files of an evolving chart

  15 octobre 2020, par James Carroll

  I am trying to make a movie of a series of charts as they change through time. I have 30 or so still versions of the chart in .png format.

  


  But when I combine them into a movie, the charts are progressively overlaid on top of each other, rather than progressing through time.

  


  I have tried several variations including :

  


  ffmpeg -r 1 -f image2 -start_number 0 -i name%2d.png -q:v 5 movie.wmv


  


  and

  


  ffmpeg -r 1/5 -start_number 1 -i name%2d.png -c:v libx264 -r 30 -pix_fmt yuv420p out.mp4


  


  All do the same thing.

  


  Any idea why this is happening ?

  


  Update 1 :

  


  git repo of sample images and failed movie here : https://github.com/jlc42/MovieTest.git

  


  Update 2 :

  


  Just in case, I tried removing the alpha channel with the following command which I found in another thread Remove alpha channel in an image :

  


  for i in `ls *.png`; do convert $i -background black -alpha remove -alpha off $i; done


  


  because my background is white, I also tried :

  


  for i in `ls *.png`; do convert $i -background white -alpha remove -alpha off $i; done


  


  I THINK I have now successfully removed the alpha channel in the images, but this did not seem to make a difference for what ffmpeg is doing.

  


• How to create video by stitching together images (.png) where the serial on each image file increases by 6

  10 avril 2024, par DataStatsExplorer

  I am trying to create a video (preferably mp4) from a series of png images. However, the name of each image file increases by 6 every frame. For example, I would have depthframe_0000 as the first frame, and depthframe_0001 for the next frame.

  


  There are a few answers that have answered a similar question but I am unable to process the video when the image files are not increasing by 1.

  


  I would like to keep the fps at 5. I am using ffmpeg as the suggested in the answers above but am open to any other suggestion.

  


  The collab code that I have put together is as follows :

  


  import subprocess

# Define the frame rate and the input/output paths
output_fps = 5
input_path = "/content/drive/MyDrive/depth/depthframe_%04d.png"
output_path = "/content/drive/MyDrive/depth.mp4"

# Create a list of the frames
frames = [input_path % i for i in range(0, 2671, 6)]  # Update range as needed

# Write the list of frames to a temporary text file
with open('frames.txt', 'w') as f:
    for frame in frames:
        f.write(f"file '{frame}'\n")

# Create the command
command = [
    "ffmpeg",
    "-f", "concat",
    "-safe", "0",
    "-i", "frames.txt",
    "-c:v", "libx264",
    "-pix_fmt", "yuv420p",
    output_path
]

# Run the command
subprocess.run(command, check=True)


  


• Encoding uncompressed avi using RAWVIDEO codec and RGB24

  21 décembre 2020, par Heimmot

  I coded an encoder using FFMPEG (c++). The requirements for this encoder are :

  


  

  1. The output format should be uncompressed avi,

  


  2. Preferably using RGB24/YUV444 pixel format since we do not want chroma subsampling.

  


  3. Most standard players should support the format (windows media player (WMP), VLC)

  


  


  Using the encoder I wrote, I can write a number of file types right now :

  


  

  1. Lossless H.264 encoded video using the YUV420p pixel format and AVI container. (Obviously not uncompressed and chroma subsampled, however both WMP and VLC play without any problem.)

  


  2. MPEG4 encoded video using the YUV420p pixel format and AVI container.(Obviously not uncompressed and chroma subsampled, however both WMP and VLC play without any problem.)

  


  3. AYUV encoded video using the YUVA444P pixel format. (uncompressed as far as I understand and not chroma subsampled. However, VLC does not play this.)

  


  4. FFV1 encoded video using the YUV444P pixel format. (lossless, and not chroma subsampled. However, WMP does not play this.)

  


  


  The above is derived from this very usefull post.

  


  So I am now looking into the RAWVIDEO encoder from FFMPEG. I can't get this to work and neither can I find an example in the FFMPEG documentation on how to use this encoder for writing video. Can somebody point me in the right direction or supply sample code for this ?
Also, if there is another direction I should follow to meet my requirements feel free to point me to it.

  


  Thanks in advance