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• ffmpeg : Missing subtitles on iPod

  7 septembre 2016, par forthrin

  I generating a playable video on a 3rd generation iPod Nano using the following command line, but I’m having certain challenges related to subtitles, stability and metadata.

  ffmpeg -y -i in.mkv -i in.srt -profile:v baseline -level 3 -refs 6 -ar 44100 -ac 2 -ab 128k
  
  -vf "scale=640:-1,pad=iw:480:0:(oh-ih)/2" -map 0:0 -map 0:1 -map 1:0 -map_metadata -1
  
  -movflags +faststart -scodec mov_text -metadata:s:s:0 language=eng out.mp4

  1. Subtitles won’t show. I tried both iPod settings "Subtitles On" and "Captions On". iPod software is latest 1.1.3. Subtitles show with OS X QuickTime after I change from "Auto" to "English" in the subtitle menu. Is there an ffmpeg flag to make subtitles display on the iPod ?

  2. The video player exits after 11-12 minutes for many of the converted videos. Restricting the bitrate -b:v 600k -bufsize 600k did not help. Any advice how to circumvent this ?

  3. Lastly, how can I make the video show under the "TV show" menu on the iPod ? Couldn’t find any help searching for "ffmpeg metadata tv". Or is this an internal iTunes feature ?

• Can't install new packages in ubuntu

  7 juin 2023, par Robbie Mallett

  I would like to install ffmpeg. My normal procedure to install this package would be :

  


  sudo apt update
sudo apt install ffmpeg


  


  However when I run sudo apt update I get some errors including :

  


    The following signatures were invalid: EXPKEYSIG 277A7293F59E4889 MiKTeX Packager <packager@miktex.org>
Reading package lists... Done
E: The repository 'http://security.ubuntu.com/ubuntu impish-security Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'http://gb.archive.ubuntu.com/ubuntu impish Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://repository.spotify.com stable InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 7A3A762FAFD4A51F
E: The repository 'http://gb.archive.ubuntu.com/ubuntu impish-updates Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'http://gb.archive.ubuntu.com/ubuntu impish-backports Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://ctan.dcc.uchile.cl/systems/win32/miktex/setup/deb focal InRelease: The following signatures were invalid: EXPKEYSIG 277A7293F59E4889 MiKTeX Packager <packager@miktex.org>


  


  And then when I run sudo apt install ffmpeg and selecting Y to some options, I get :

  


  (base) robbie@ro-rmallett-l1:~$ sudo apt install ffmpeg
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following package was automatically installed and is no longer required:
  libfwupdplugin1
Use 'sudo apt autoremove' to remove it.
The following additional packages will be installed:
  libavdevice58 libdc1394-25 libopenal-data libopenal1 libsdl2-2.0-0
Suggested packages:
  ffmpeg-doc libportaudio2
The following NEW packages will be installed
  ffmpeg libavdevice58 libdc1394-25 libopenal-data libopenal1 libsdl2-2.0-0
0 to upgrade, 6 to newly install, 0 to remove and 19 not to upgrade.
Need to get 3,046 kB of archives.
After this operation, 5,642 kB of additional disk space will be used.
Do you want to continue? [Y/n] Y
WARNING: The following packages cannot be authenticated!
  libdc1394-25 libopenal-data libopenal1 libsdl2-2.0-0 libavdevice58 ffmpeg
Install these packages without verification? [y/N] Y
Err:1 http://gb.archive.ubuntu.com/ubuntu impish/universe amd64 libdc1394-25 amd64 2.2.6-3
  404  Not Found [IP: 185.125.190.36 80]
Ign:2 http://gb.archive.ubuntu.com/ubuntu impish/universe amd64 libopenal-data all 1:1.19.1-2
Err:3 http://gb.archive.ubuntu.com/ubuntu impish/universe amd64 libopenal1 amd64 1:1.19.1-2
  404  Not Found [IP: 185.125.190.36 80]
Ign:4 http://gb.archive.ubuntu.com/ubuntu impish-updates/main amd64 libsdl2-2.0-0 amd64 2.0.14+dfsg2-3ubuntu0.1
Ign:5 http://gb.archive.ubuntu.com/ubuntu impish-updates/universe amd64 libavdevice58 amd64 7:4.4.2-0ubuntu0.21.10.1
Ign:6 http://gb.archive.ubuntu.com/ubuntu impish-updates/universe amd64 ffmpeg amd64 7:4.4.2-0ubuntu0.21.10.1
Err:2 http://gb.archive.ubuntu.com/ubuntu impish/universe amd64 libopenal-data all 1:1.19.1-2
  404  Not Found [IP: 185.125.190.36 80]
Err:4 http://security.ubuntu.com/ubuntu impish-updates/main amd64 libsdl2-2.0-0 amd64 2.0.14+dfsg2-3ubuntu0.1
  404  Not Found [IP: 185.125.190.36 80]
Err:5 http://security.ubuntu.com/ubuntu impish-updates/universe amd64 libavdevice58 amd64 7:4.4.2-0ubuntu0.21.10.1
  404  Not Found [IP: 185.125.190.36 80]
Err:6 http://security.ubuntu.com/ubuntu impish-updates/universe amd64 ffmpeg amd64 7:4.4.2-0ubuntu0.21.10.1
  404  Not Found [IP: 185.125.190.36 80]
E: Failed to fetch http://gb.archive.ubuntu.com/ubuntu/pool/universe/libd/libdc1394/libdc1394-25_2.2.6-3_amd64.deb  404  Not Found [IP: 185.125.190.36 80]
E: Failed to fetch http://gb.archive.ubuntu.com/ubuntu/pool/universe/o/openal-soft/libopenal-data_1.19.1-2_all.deb  404  Not Found [IP: 185.125.190.36 80]
E: Failed to fetch http://gb.archive.ubuntu.com/ubuntu/pool/universe/o/openal-soft/libopenal1_1.19.1-2_amd64.deb  404  Not Found [IP: 185.125.190.36 80]
E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/libs/libsdl2/libsdl2-2.0-0_2.0.14%2bdfsg2-3ubuntu0.1_amd64.deb  404  Not Found [IP: 185.125.190.36 80]
E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/universe/f/ffmpeg/libavdevice58_4.4.2-0ubuntu0.21.10.1_amd64.deb  404  Not Found [IP: 185.125.190.36 80]
E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/universe/f/ffmpeg/ffmpeg_4.4.2-0ubuntu0.21.10.1_amd64.deb  404  Not Found [IP: 185.125.190.36 80]
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?


  


  When I use --fix-missing after either call it doesn't help. To be honest I can't understand the error messages. I'm running Ubuntu 21.10. What should I do ? I can't seem to install any new packages with apt-get.

  


• Implementing Live Streaming Webinar Architecture - Need Guidance

  21 septembre 2023, par vishnugpl

  Question : I'm working on a project to implement a live streaming webinar platform, and I'm looking for guidance on the architecture and technologies to use. I have some specific requirements and constraints, and I'd appreciate any advice or pointers on how to get started.

  


  Context :
I'm tasked with building a live streaming webinar platform from scratch for our organization. Here are some key requirements and constraints :

  


  


  1. Live Video Streaming : We need to support live video streaming for
webinars, workshops, and conferences. Low latency is crucial for
real-time interaction between presenters and attendees.

     


  


  2. Scalability : The platform should be able to handle a large number of concurrent attendees, potentially thousands or more,
without compromising performance.

     


  


  3. Security : Security is a top priority. We need to ensure that only authorized users can access the webinars, and we must protect
against unauthorized recording or distribution of the content.

     


  


  4. User Interaction : Attendees should be able to ask questions, participate in polls, and interact with presenters in real-time.

     


  


  5. Recording and Playback : We also want to provide recorded versions of past webinars for on-demand viewing (HLS).

     


  


  


  Current Tech Stack :

  


  

  • Frontend : React

  


  • Backend : Node.js with Express

  


  • Database : MongoDB

  


  • Cloud Hosting : AWS

  


  


  Questions :

  


  


  • What technologies or services are best suited for handling live video streaming with low latency ?

    


  


  • How can I ensure scalability in terms of both video streaming and handling a large number of users ?

    


  


  • What security measures should I consider to protect the content and user data ?

    


  


  • Are there any recommended frameworks or libraries for building interactive features like real-time chat and polling ?

    


  


  • What's the best approach for recording and serving on-demand webinar content ?

    


  


  


  Additional Information :

  


  


  • Budget is a consideration, so cost-effective solutions are preferred.

    


  


  • Any open-source or third-party tools that can simplify development are welcome.

    


  


  • I have experience with AWS, but I'm open to other cloud providers if they offer advantages for this project.