Recherche avancée

Sur d’autres sites (5929)

• Swift : How can I generate Mp4 video from programmaticall output ? [closed]

  21 août 2020, par Mount Ain

  This question is specifically to Swift programming language for Linux & macOS platforms.To understanding the concept, I used Swift programming language. But not depend on Swift programming language. C or C++ is also good to me.

  


  I can generate JPEG image from NSView by using NSBitmapImageRep. But Linux I don't what I want to do. So, the first thing I need to know is the step to generate JPEG image by programmatically without using the NSView. I really don't know How hard it is. But I want to learn how it's work. I feel It's the way to fill the color into pixels one by one to combine a Image. But I don't know How to do in programming. I knew the same way is used in videos by packing the series of image with audio & subtitle & other meta info.

  


  If you ask about compression, I really want to know How Twitter & YouTube compressing uploaded videos without loss of quality.

  


  So what is the concept,

  


  

  1. To generate a JPEG image by programmatically without using NSView ?

  


  2. To generate MPEG-4 video by group of JPEG images ?

  


  


  Thanking in advance...

  


• How to chose the default audio track on IOS HLS

  18 juillet 2020, par Maxou

  when I set my default audio track in my playlist with the "DEFAULT" params the IOS native player doesn't choose the right one. For example with the playlist below IOS choose the french audio track

  


  this is my playlist file :

  


  #EXTM3U
#EXT-X- VERSION:3

#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="audio",LANGUAGE="jpn",NAME="Japonais",DEFAULT=YES,AUTOSELECT=YES,URI="audio/1/128kbit.m3u8"
#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="audio",LANGUAGE="fre",NAME="Français",DEFAULT=NO,AUTOSELECT=YES,URI="audio/2/128kbit.m3u8"

#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="subs",NAME="Français",DEFAULT=YES,AUTOSELECT=YES,FORCED=NO,LANGUAGE="fr",URI="subtitles_fr.m3u8"

#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=9000000,AUDIO="audio",SUBTITLES="subs"
video/index.m3u8


  


  Any ideas ?

  


• Looping Variables in a Batch File (for use with FFmpeg)

  16 avril 2021, par OrdinaryCarrot16

  I am creating a batch script that stores the input of the user into variables, that will later be used for creating converting files then adding metadata (via FFmpeg). It is working pretty good, now I'm just trying to figure out how to loop the FFmpeg line that uses all the variables the user inputted, and it will loop the command till it reaches the number specified in the 'track_amount' variable.

  


  Do you have any ideas on how to make this work ? Thanks !

  


  setlocal enabledelayedexpansion

:: Scan current directory for audio files
DIR *.mp3 OR *.m4a

set /P cover-art=Select the Audio/Image File with the Cover Art (ex. MP3/M4A or JPG/PNG): 
set /P artist=Artist/Band Name: 
set /P track_amount=How many tracks are in this album: 

if %track_amount% GTR 1 (
    set /P album=Album Name: 
)

set /P filename=Song File Name: 
set /P title=Song Name: 
set /P track=Track Number: 
set /P genre=Genre: 
set /P language=Language: 

ffmpeg -i "%cover-art%" -vf scale=512:512 -sws_flags bicubic cover_tmp.png

for %%t in (!track_amount!) do ffmpeg -i "%filename%" -i cover_tmp.png -map_metadata -1 -map 0:0 -map 1:0 -id3v2_version 3 -metadata artist="%artist%" -metadata album="%album%" -metadata title="%title%" -metadata track="%track%/%track_amount%" -metadata genre="%genre%" -metadata language="%language%" -c:1 png -disposition:1 attached_pic -c:a libmp3lame -ar 44100 -b:a 160k "%title%.mp3"

pause