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• FFmpeg Libraries : How Do I Convert a Video to 4 Level Grayscale Video at 160x100 Pixels and as Raw Data

  15 avril 2014, par pimathbrainiac

  This seems like an odd question, so I am going to start from the beginning :

  I am a calculator programmer, specifically a Ti-89 programmer, and I'm trying to make a video player for it. I have the code for the calculator side done already, but I need to be able to convert video to a specific format that works as follows :

  Each frame is 4 level grayscale, where there are 2 bytes for every 8 horizontal pixels, a "back," or dark byte, and a "front," or light byte. Basically, every frame is 2 monochrome binary images, with the first byte of the first one is followed by the first byte of the second one, so data is stored as follows :

  FB(front buffer)[1],BB(back buffer)[1],FB[2],BB[2], etc...

  Here's how the display works : (defining 0 as white and 3 as black, with 1 and 2 being in-between shades)
  Each front buffer bit is worth 1, so if the front buffer were displayed with nothing in the back buffer, the "1" (or true) bits would show up as light gray pixels. These are then added to the back buffer bits, which are worth 2 (so if the back buffer were displayed with nothing in the front buffer, the "1" (or true) bits would show up as dark gray pixels) to get :

  "0" bit on either buffer = white pixel (0+0=0)

  "1" bit on front buffer but not back buffer = light gray pixel (1+0=1)

  "1" bit on back buffer but not front buffer = dark gray pixel (0+2=2)

  "1" bit on both buffers = black pixel (1+2=3)

  I have this down calculator-side, but I need to know : 1) How to convert the video to a specific framerate using the libs 2) How to convert these frames to 4-level grayscale at 160x100 pixels and 3) How to save these frames as raw data in the format I described. Thank you in advance for your answer(s).

• File Convert from mp4/mp3 to G.723.1 and H.263 FFMpeg

  24 décembre 2013, par Atanu Saha

  I am new in ffmpeg and using version 2.0.2 in my linux server.

  1) Could anyone please tell me how i can convert from mp4/mp3 files to G.723.1 file format and G.723.1 to mp4 ?

  2) I was using following command for conversion from mp4 to H.263

  ffmpeg -i input.mp4 output.h263

  It was working fine in version 0.6.5. but in version 2.0.2, it does not work. But if i use h264, it works fine !

  Thank you to give me of your valuable time.

• First input link main timebase (1/15360) do not match the corresponding second input link xfade timebase (1/90000)

  14 novembre 2023, par Rino

  coders

  


  I am new to ffmpeg and i am facing this error for more then 2 days.
This ffmpeg command :
!ffmpeg -i "{fromPath}" -i "{toPath}" -filter_complex "xfade=transition={chosenTransition}:duration={transitionDuration}:offset=-1.5" -c:v libx264 -crf 18 -preset veryfast "{outPath}"
I run that previous command 3 times in row where output of the previous command is input that is getting produced as 15360 timebase video i guess.

  


  is giving me this error : "First input link main timebase (1/15360) do not match the corresponding second input link xfade timebase (1/90000)"

  


  So when i merge two of my videos the output is video with (1/15360) timebase. Original videos has (1/90000) timebase.

  


  Pls help what i wana archive is basicly multiple videos inside a folder called "clips" merge together using a random transition from xfade/ffmpeg.

  


  On colab i tried all this ways :

  


  !rm -rf chunks
!mkdir chunks
time.sleep(1)
folderPath = '/content/clips'
videoOutput = '/content/test.mp4'
transitionDuration = 6

videoFiles = [f"{folderPath}/{f}" for f in os.listdir(folderPath) if f.endswith('.mp4')]
random.shuffle(videoFiles)
fromPath = videoFiles[0]
toPath = ''
outPath = ''
transitions = ['fade', 'wipeup', 'slidedown', 'circleclose', 'radial' , 'hrslice', 'hblur', 'smoothleft', 'smoothright']

for videoIndex, videoName in enumerate(videoFiles):
    if videoIndex == 0:
        continue
    toPath = videoName
    chosenTransition = random.choice(transitions)
    print('chosenTransition', chosenTransition)
    clipDuration = int((imageio.get_reader(fromPath)).get_meta_data()['duration']) - transitionDuration
    # !echo -i /content/clips/clip0.mp4 -i /content/clips/clip1.mp4 -filter_complex xfade=transition={chosenTransition}:duration=3:offset={clipDuration} dissolveVideo.mp4

    if videoIndex == len(videoFiles) - 1:
        outPath = videoOutput
    else:
        outPath = f'/content/chunks/chunk{videoIndex}.mp4'
    time.sleep(2)
    
    # !echo -i "{fromPath}" -i "{toPath}" -filter_complex "[0:v]xfade=transition={chosenTransition}:duration=3:offset={clipDuration},settb=1/19000[v0];[0:a][1:a]acrossfade=d=3[aout]" -map "[v0]" -map "[aout]" -c:v libx264 -crf 18 -preset ultrafast "{outPath}"
    !ffmpeg -i "{fromPath}" -i "{toPath}" -filter_complex "xfade=transition={chosenTransition}:duration={transitionDuration}:offset=-1.5,settb=1/15360" -c:v libx264 -crf 18 -preset veryfast "{outPath}"
    # !ffmpeg -i "{fromPath}" -i "{toPath}" -filter_complex "[0:v]settb=1/15360,setpts=PTS-STARTPTS[v0];[1:v]settb=1/15360,setpts=PTS-STARTPTS[v1];[v0][v1]xfade=transition={chosenTransition}:duration={transitionDuration}:offset=-1.5[vout]" -map "[vout]" -c:v libx264 -crf 18 -preset ultrafast "{outPath}"
    # !ffmpeg -i "{fromPath}" -i "{toPath}" -filter_complex "[0]settb=AVTB [0v]; [1]settb=AVTB [1v]; [0v] [1v]xfade=transition={chosenTransition}:duration={transitionDuration}:offset=1" -c:v libx264 -crf 18 -preset ultrafast "{outPath}"
    # !ffmpeg -i "{fromPath}" -i "{toPath}" -filter_complex "[0:v]xfade=transition={chosenTransition}:duration=3:offset={clipDuration},settb=1/15360[v0];[0:a][1:a]acrossfade=d=3[aout]" -map "[v0]" -map "[aout]" -c:v libx264 -crf 18 -preset ultrafast "{outPath}"
    # !ffmpeg -y -progress .progressinfo.dat -i "{fromPath}" -i "{toPath}" -filter_complex "[0:v]settb=AVTB,setpts=PTS-STARTPTS[v0];[1:v]settb=AVTB,setpts=PTS-STARTPTS[v1];[v0][v1]xfade=transition={chosenTransition}:duration={transitionDuration}:offset={clipDuration}[vout];[0:a]asettb=AVTB,asetpts=PTS-STARTPTS[a0];[1:a]asettb=AVTB,asetpts=PTS-STARTPTS[a1];[a0][a1]acrossfade=d=3[aout]" -map "[vout]" -map "[aout]" -c:v libx264 -crf 18 -preset ultrafast "{outPath}"