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• Can you reuse an init.mp4 file for two separate FMP4 videos if they are encoded to the same specification ?

  19 février 2024, par TCR

  I have two separate FMP4 (Fragmented MP4) videos that I need to encode. Both videos will be encoded to the same specifications, including resolution, bitrate, and codec settings. I understand that each FMP4 video typically includes an init.mp4 file containing initialization data.

  


  My question is : can I reuse the same init.mp4 file for both videos since they are encoded to the same spec ? Would this cause any issues with playback compatibility or any other potential problems ?

  


  Since the moov atom contains general info and timing information meta-data, and both videos are encoded to the same specification, my thought is you could reference one init file for playback of both videos. If I could guarantee that encoding specifications are the same, what would be the consequence of such an approach ?

  


• lavfi/perspective : Add basic timeline editing.

  10 avril 2016, par Thilo Borgmann

  lavfi/perspective : Add basic timeline editing.
  Add number of input and output frames to possible variables.
  
  Add option eval to reevaluate coordinate expressions during
  
  initialization or for every frame.
  

  • [DH] doc/filters.texi
  • [DH] libavfilter/vf_perspective.c

• Specifying FFMPEG in the requirements section of 'buildozer.spec' causing [libavformat/network.o] Error 1

  18 juillet 2022, par GJ78

  My question relates to how to mitigate an ffmpeg requirement listed in a buildozer.spec that is causing compile errors using buildozer.

  



  GOAL :

  



  Using buildozer to ensure FFMPEG can be embedded within a small Kivy app so i can utilise youtube_dl functionality on my android phone.

  



  THE ISSUE :
Specifying FFMPEG in the requirements section of 'buildozer.spec' causes the following error message :
  
common.mak:60 : recipe for target 'libavformat/network.o' failed
  
make : [libavformat/network.o] Error 1
  
make : Waiting for unfinished jobs...

  



  What have I done to resolve myself :
  
1. Ensured LOG LEVEL 2 is specified.

  



  


  2. Upgraded cython from Version 21 to 27. Then downgraded to 25, then 21 then 20 to see if this resolved anything. It didn't.

  


  3. In BUILDOZER.SPEC, switched between Android NDK crystax-ndk-10.3.2 and android-ndk-r16b. (Note have reverted back to Crystax 10.3.2) in my NDK PATH.

  


  4. In BUILDOZER.SPEC, changed android.api from 19 to 15 (just to see if this has any positive effects).

  


  5. executed : rm -Rf .buildozer between each compiling attempt.

  


  6. Part extract of Buildozer.log :

     



     In file included from libavformat/dump.c:37:0 :
     
libavformat/avformat.h:893:21 : note : declared here
     
 AVCodecContext codec ;
 ^
     
CC libavformat/format.o
     
CC libavformat/golomb_tab.o
     
CC libavformat/h264dec.o
     
CC libavformat/hevc.o
     
CC libavformat/http.o
     
CC libavformat/httpauth.o
     
CC libavformat/id3v1.o
     
CC libavformat/id3v2.o
     
CC libavformat/img2.o
     
CC libavformat/isom.o
     
CC libavformat/log2_tab.o
     
CC libavformat/m4vdec.o
     
CC libavformat/metadata.o
CC libavformat/mov_chan.o
     
CC libavformat/mov.o
     
CC libavformat/movenc.o
     
CC libavformat/movenccenc.o
     
CC libavformat/movenchint.o
     
CC libavformat/mpegvideodec.o
     
CC libavformat/mux.o
     
CC libavformat/network.o
     
In file included from libavformat/network.h:29:0,
     
 from libavformat/network.c:22 :
     
libavformat/os_support.h:67:32 : error : expected declaration specifiers or '...' before '(' token
     
 # define lseek(f,p,w) lseek64((f), (p), (w))
     
 ^
libavformat/os_support.h:67:37 : error : expected declaration specifiers or '...' before '(' token
     
 # define lseek(f,p,w) lseek64((f), (p), (w))
     
 ^
libavformat/os_support.h:67:42 : error : expected declaration specifiers or '...' before '(' token
     
 # define lseek(f,p,w) lseek64((f), (p), (w))
     
 ^
common.mak:60 : recipe for target 'libavformat/network.o' failed
     
make : [libavformat/network.o] Error 1
     
make : * Waiting for unfinished jobs....

  


  7. Part extract of Buildozer.spec

     



     (str) Title of your application

     



     title = myapplication

     



     (str) Package name

     



     package.name = myapp

     



     (str) Package domain (needed for android/ios packaging)

     



     package.domain = org.test

     



     (str) Source code where the main.py live

     



     source.dir = .

     



     (list) Source files to include (let empty to include all the files)

     



     source.include_exts = py,png,jpg,kv,atlas

     



     (list) List of inclusions using pattern matching

     



     source.include_patterns = assets/,images/.png

     



     (list) Source files to exclude (let empty to not exclude anything)

     



     source.exclude_exts = spec

     



     (list) List of directory to exclude (let empty to not exclude anything)

     



     source.exclude_dirs = tests, bin

     



     (list) List of exclusions using pattern matching

     



     source.exclude_patterns = license,images//.jpg

     



     (str) Application versioning (method 1)

     



     version = 0.1

     



     (str) Application versioning (method 2)

     



     version.regex = version = '"['"]

     



     version.filename = %(source.dir)s/main.py

     



     (list) Application requirements

     



     comma seperated e.g. requirements = sqlite3,kivy

     



     requirements = ffmpeg,python2,hostpython2,kivy,youtube-dl

     



     (str) Custom source folders for requirements

     



     Sets custom source for any requirements with recipes

     



     requirements.source.kivy = ../../kivy

     



     (list) Garden requirements

     



     garden_requirements =

     



     (str) Presplash of the application

     



     presplash.filename = %(source.dir)s/data/presplash.png

     



     (str) Icon of the application

     



     icon.filename = %(source.dir)s/data/icon.png

     



     (str) Supported orientation (one of landscape, portrait or all)

     



     orientation = portrait

     



     (list) List of service to declare

     



     services = NAME:ENTRYPOINT_TO_PY,NAME2:ENTRYPOINT2_TO_PY

     



     OSX Specific

     



     author = © Copyright Info

     



     change the major version of python used by the app

     



     osx.python_version = 3

     



     Kivy version to use

     



     osx.kivy_version = 1.9.1

     



     Android specific

     



     (bool) Indicate if the application should be fullscreen or not

     



     fullscreen = 0

     



     (string) Presplash background color (for new android toolchain)

     



     Supported formats are : #RRGGBB #AARRGGBB or one of the following names :

     



     red, blue, green, black, white, gray, cyan, magenta, yellow, lightgray,

     



     darkgray, grey, lightgrey, darkgrey, aqua, fuchsia, lime, maroon, navy,

     



     olive, purple, silver, teal.

     



     android.presplash_color = #FFFFFF

     



     (list) Permissions

     



     android.permissions = INTERNET

     



     (int) Android API to use

     



     android.api = 19

     



     (int) Minimum API required

     



     android.minapi = 9

     



     (int) Android SDK version to use

     



     android.sdk = 20

     



     (str) Android NDK version to use

     



     android.ndk = 10.3.2

     



     (bool) Use —private data storage (True) or —dir public storage (False)

     



     android.private_storage = True

     



     (str) Android NDK directory (if empty, it will be automatically downloaded.)

     



     android.ndk_path = /home/gjones/Downloads/crystax-ndk-10.3.2

     



     (str) Android SDK directory (if empty, it will be automatically downloaded.)

     



     android.sdk_path =

     



     (str) ANT directory (if empty, it will be automatically downloaded.)

     



     android.ant_path =

  


  8. Lastly, when I remove ffmpeg from requirements in buildozer.spec, the .APK compiles successfully and i can deploy it on to my phone with the KIVY GUI. Obviously, ffmpeg functionality is not present.

  


  



  Current Environment Specs :

  



  

  1. Running Linux Mint 17.2 as a Virtual Box VM

  


  2. Buildozer Version : 0.35dev

  


  3. Cython Version : 0.25

  


  



  Any advice would be greatly appreciated.

  



  Lastly, if there is no obvious solution via buildozer, do i need to compile ffmpeg for Android separately and somehow include this somewhere in the buildozer spec file to prevent this error message ?

  



  Thanks in advance.