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• Image generated by System.Drawing.Image is 10x larger than original file

  13 mai 2021, par Ninbura

  I've written a Powershell script that extracts one frame from a dshow capture device using FFmpeg, and then copies the output image from a file to my clipboard :

  


  $screenshot = [System.Drawing.Image]::FromFile((Get-Item -Path $outputFilePath))
[System.Windows.Forms.Clipboard]::SetImage($screenshot)
$screenshot.Dispose()


  


  The original file is a 1MB JPEG, but the image in my clipboard is an 11MB PNG. When I go to paste this file into something like Discord the file size is too large, unless you have Discord Nitro.

  


  Is there any way to avoid this file size inflation while using [System.Drawing.Image]::FromFile() ?

  


  Here's an easy test template :

  


  Add-Type -AssemblyName System.Drawing
Add-Type -AssemblyName System.Windows.Forms

$screenshot = [System.Drawing.Image]::FromFile((Get-Item -Path "Path to picture"))
[System.Windows.Forms.Clipboard]::SetImage($screenshot)
$screenshot.Dispose()


  


  Edit 2021/05/13 :

  


  Interestingly, it's starting to seem like this is a limitation of copying an image to a clipboard. I decided to dig deeper and see if the image size was increasing when I drew the image with System.Drawing.Image or when I pushed it in my clipboard with System.Windwos.Forms.Clipboard. If I save the image before putting it my clipboard like so, it retains the original file size, even if I change the extension to png :

  


  Add-Type -AssemblyName System.Drawing
Add-Type -AssemblyName System.Windows.Forms

$screenshot = [System.Drawing.Image]::FromFile((Get-Item -Path "C:\Users\gabri\Pictures\FFScreenshots\2021-05-12 19-04-26.845.jpeg"))
$screenshot.Save("C:\Users\gabri\Pictures\FFScreenshots\test.jpeg") # test.png makes no difference
$screenshot.Dispose()


  


  So it would seem that the image grows exponentially in size specifically when I push it to my clipboard. I verified this by simply uploading an image to Discord, copying it to my clipboard (click image > Open original > right click and copy result), and uploading it again. Sure enough, the new image pasted from my clipboard was around 10x the size of the original image (1MB vs 12MB). I wondered if this was a "limitation" of Windows so I ran the same test on Ubuntu 20.04. Uploaded an image to Discord, copied the image to my clipboard, and uploaded it again. Once again the image was about 10x larger, though slightly smaller than then when I uploaded the image from my clipboard on my Windows machine (11.4MB VS 12MB). Just to make sure this wasn't limited to Discord, I ran the same test with Gmail in-browser on both operating systems, same result.

  


  Alas, there appears to be something happening when you copy an image to a clipboard that drastically increases file size. One thing's for sure, whatever's happening is definitely over my head.

  


• Mpeg Dash code having compilation issues and want to know what to do after the code is built and how to play the .mpd file generated

  11 avril 2013, par niuuuu

  I'm trying to build the DashEncoder code which I downloaded from github https://github.com/slederer/DASHEncoder. Well, I followed all the instructions given in the how to compile dash file. installed Gpac n X264 and compiled both successfully. Then did make of Dashencoder and ran it as ./Dashencoder. But I found some issues in it. Got this log :

  ==========DASH ENCODER===============
  
  Unknown option in resourcefile : sql-pw :
  
  current encoder x264
  
  YES
  
  x264 encoding @ 300 kbps: Pass 1 
  
  x264: x264 --profile baseline --preset slow --verbose --fps 24 --vbv-maxrate 300 --vbv-bufsize 600 --scenecut 0 --keyint 48 --output /opt/lampp/htdocs/tests_updates/sintel_trailer_2k_480p24_300kbit.h264 /home/niu/sintel_trailer_2k_480p24.y4m >out.txt 2>&1 
  
  mkdir: cannot create directory `/opt/lampp/htdocs/tests_updates/sintel_300kbit': File exists
  
  cp: omitting directory `/opt/lampp/htdocs/tests_updates/'
  
  copy audio: cp /opt/lampp/htdocs/tests_updates/ /opt/lampp/htdocs/tests_updates/sintel_300kbit/MP4Box multiplexing Video: /opt/lampp/htdocs/tests_updates/sintel_300kbit/sintel_trailer_2k_480p24_300kbit.h264  
  
  mp4box: MP4Box -add /opt/lampp/htdocs/tests_updates/sintel_300kbit/sintel_trailer_2k_480p24_300kbit.h264  /opt/lampp/htdocs/tests_updates/sintel_300kbit/sintel_trailer_2k_480p24_300kbit.mp4
  
  AVC-H264 import - frame size 854 x 480 at 24.000 FPS
  
  AVC Import results: 1253 samples - Slices: 27 I 1226 P 0 B - 1 SEI - 27 IDR
  
  Saving to /opt/lampp/htdocs/tests_updates/sintel_300kbit/sintel_trailer_2k_480p24_300kbit.mp4: 0.500 secs Interleaving
  
  MP4Box multiplexing Audio:/opt/lampp/htdocs/tests_updates/sintel_300kbit/ 
  
  mp4box: MP4Box -add /opt/lampp/htdocs/tests_updates/sintel_300kbit/ /opt/lampp/htdocs/tests_updates/sintel_300kbit/sintel_trailer_2k_480p24_300kbit.mp4
  
  Unknown input file type
  
  Unknown input file type
  
  Error importing /opt/lampp/htdocs/tests_updates/sintel_300kbit/: Bad Parameter
  
  MP4Box Cleaning ... 
  
  mp4box: MP4Box -no-sys  /opt/lampp/htdocs/tests_updates/sintel_300kbit/sintel_trailer_2k_480p24_300kbit.mp4
  
  Saving /opt/lampp/htdocs/tests_updates/sintel_300kbit/sintel_trailer_2k_480p24_300kbit.mp4: 0.500 secs Interleaving
  
  MP4Box segmentation: /opt/lampp/htdocs/tests_updates/sintel_300kbit/sintel_trailer_2k_480p24_300kbit.h264  
  
  mp4box: MP4Box -frag 2000 -dash 2000 -rap -segment-name /opt/lampp/htdocs/tests_updates/sintel_300kbit/sintel /opt/lampp/htdocs/tests_updates/sintel_300kbit/sintel_trailer_2k_480p24_300kbit.mp4
  
  DASH-ing file: 2.00s segments 2.00s fragments single sidx per segment
  
  Spliting segments at GOP boundaries
  
  [DASH] Generating MPD at time 2013-03-16T16:40:03Z
  
  DASHing file /opt/lampp/htdocs/tests_updates/sintel_300kbit/sintel_trailer_2k_480p24_300kbit.mp4
  
  terminate called after throwing an instance of 'std::out_of_range'
  
    what():  basic_string::substr
  
  Error: Unable to open MPD file!Aborted

  Why is this error at the end ?
  and also one folder got created in my /opt/lampp/htdocs/tests_updates/sintel_300kbit.
  which has two types of files :
  27 files of .m4s extension
  1 file -sintelinit.mp4
  1 file- sintel_trailer_2k_480p24_300kbit.mp4 , which when played in vlc player played the video bt no audio ! &

  1 file- sintel_trailer_2k_480p24_300kbit.h264 which cannot be opened.

  No .mpd file was created.

  Also I want to know aft creating that .mpd file how will i be able to test it on my android client say media player.

  I am damn confused with all this happening. Please help.

• Bash script to automate FFmpeg operations fails when calling the command, but copy-pasting the generated command into the terminal works [duplicate]

  28 février, par GaboScharff99

  I wrote a bash script which automates a number of conversion operations on video files using FFmpeg. Oddly enough, the FFmpeg call itself now fails when running the script, with a very confusing error message, I might add, but when I copy the command generated by the script into the terminal and run it, it works flawlessly. I'm sorry to insert such a long code block here, but considering how strange this error is, it might be anywhere in the script, so here it is :

  


  #!/bin/bash

audioTrack=1
subSource=1
subTrack=0
transcodeVideo=1
transcodeAudio=1
volumeMultiplier=1
degradeToStereo=0
subLanguage="Japanese"

while getopts "t:ns:vam:dl:h" opt; do
    case "$opt" in
        t) audioTrack=${OPTARG};;
        n) subSource=0;;
        s) subTrack=${OPTARG};;
        v) transcodeVideo=0;;
        a) transcodeAudio=0;;
        m) volumeMultiplier=${OPTARG};;
        d) degradeToStereo=1;;
        l) subLanguage=${OPTARG};;
        h)
            echo "Options:"
            echo "-t [integer]: Audio track number. Default: 1."
            echo "-n: If included, subtitles will be taken from internal source."
            echo "-s [integer]: Subtitles track number. Default: 0."
            echo "-v: If included, video source will be copied without transcoding."
            echo "-a: If included, audio source will be copied without transcoding."
            echo "-m [number]: Volume multiplier. If 1, volume is unaffected. Default: 1"
            echo "-d: If included, audio will be degraded to stereo."
            echo "-l [language]: Subtitles language. Only used for external subtitles source. Default: Japanese."
            exit 0
        ;;
    esac
done

echo "Audio track: $audioTrack."
echo "Subtitles track: $subTrack."
params="-map 0:0 -map 0:$audioTrack -map $subSource:$subTrack -c:v"

if [[ $transcodeVideo -eq 1 ]]; then
    echo "Video will be transcoded."
    params="$params hevc"
elif [[ $transcodeVideo -eq 0 ]]; then
    echo "Video will be copied without transcoding."
    params="$params copy"
fi

params="$params -c:a"

if [[ $transcodeAudio -eq 1 ]]; then
    echo "Audio will be transcoded."
    params="$params libopus"
elif [[ $transcodeAudio -eq 0 ]]; then
    echo "Audio will be copied without transcoding."
    params="$params copy"
fi

if [[ $volumeMultiplier -ne 1 ]]; then
    echo "Volume will be multiplied by a factor of $volumeMultiplier."
    params="$params -filter:a 'volume=$volumeMultiplier'"
else
    echo "Volume will be unaffected."
fi

if [[ $degradeToStereo -eq 1 ]]; then
    echo "Audio will be degraded to stereo."
    params="$params -ac 2"
elif [[ $degradeToStereo -eq 0 ]]; then
    echo "Audio will not be degraded to stereo."
fi

params="$params -c:s copy"

if [[ $subSource -eq 1 ]]; then
    echo "Subtitles source is external."
    echo "Subtitles language is $subLanguage."
    params="$params -metadata:s:s:0 title='' -metadata:s:s:0 language='$subLanguage'"
else
    echo "Subtitles source is internal."
fi

if [[ -f titles.txt ]]; then
    echo "A titles.txt file was found. Titles will be changed according to it."
    echo "Please check titles.txt to make sure the titles are correct."
    changeTitles=1
    counter=0
else
    echo "A titles.txt file was not found. Titles will not be changed."
    changeTitles=0
fi

read -p "Are these options correct? (y/n) " choice

case "$choice" in
    y|Y)
        echo "Initiating conversion sequence. This may take a while..."

        mkdir output
        currentParams=""

        shopt -s nullglob
        for i in *.mp4 *.mkv; do
            currentParams=$params
            fileNameNoExtension=$(echo $i | rev | cut -f 2- -d '.' | rev)

            if [[ $subSource -eq 1 ]]; then
                currentParams="-f srt -i $fileNameNoExtension.srt $currentParams"
            fi

            if [[ $changeTitles -eq 1 ]]; then
                ((counter++))
                currentParams="$currentParams -metadata title='$(awk "NR==$counter" titles.txt)'"
            fi

            ffmpeg -i "$i" $currentParams "output/$fileNameNoExtension.mkv"
        done

        echo "Conversion finished!"
    ;;
    n|N) echo "Operation canceled. Exiting.";;
    *) echo "Invalid input. Try again.";;
esac


  


  The directory I'm running this in contains six video files :

  


  

  1. E1 - The Pirates of Orion.mkv

  


  2. E2 - Bem.mkv

  


  3. E3 - The Practical Joker.mkv

  


  4. E4 - Albatross.mkv

  


  5. E5 - How Sharper Than a Serpent's Tooth.mkv

  


  6. E6 - The Counter-Clock Incident.mkv

  


  


  Here's the titles.txt file, for completion's sake :

  


  Star Trek: The Animated Series - Season 2, Episode 1 - The Pirates of Orion
Star Trek: The Animated Series - Season 2, Episode 2 - Bem
Star Trek: The Animated Series - Season 2, Episode 3 - The Practical Joker
Star Trek: The Animated Series - Season 2, Episode 4 - Albatross
Star Trek: The Animated Series - Season 2, Episode 5 - How Sharper Than a Serpent's Tooth
Star Trek: The Animated Series - Season 2, Episode 6 - The Counter-Clock Incident


  


  And finally, here's the error message given by FFmpeg on the terminal for every video file when running the command :

  


  Unable to find a suitable output format for 'Trek:'
Trek:: Invalid argument


  


  Maybe there are better ways to handle all of this, but first and foremost, I would like to figure out why the command fails with such a confusing error message. The only place where the string 'Trek :' is found is in the title taken from titles.txt, but I don't understand why that's seemingly being passed to the name of the output file instead of the title, and apparently only when running the script.

  


  Thanks a lot for your answers ! I know this is quite a bit of text, so I really appreciate you taking your time to read through this.