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• Rails 5 - Video streaming using Carrierwave uploaded video size constraint on the server

  21 mars 2020, par Milind

  I have a working Rails 5 apps using Reactjs for frontend and React dropzone uploader to upload video files using carrierwave.

  So far, what is working great is listed below -

  1. User can upload videos and videos are encoded based on the selection made by user - HLS or MPEG-DASH for online streaming.
  2. Once the video is uploaded on the server, it starts streaming it by :-
     • FIRST,copying video on /tmp folder.
     • Running a bash script that uses ffmpeg to transcode uploaded video using predefined commands to produce new fragments of videos inside /tmp folder.
     • Once the background job is done, all the videos are uploaded on AWS S3, which is how the default carrierwave works
  3. So, when multiple videos are uploaded, they are all copied in /tmp folder and then transcoded and eventually uploaded to S3.

  My questions, where i am looking some help are listed below -

  1- The above process is good for small videos, BUT what if there are many concurrent users uploading 2GB of videos ? I know this will kill my server as my /tmp folder will keep on increasing and consume all the memory, making it to die hard.How can I allow concurrent videos to upload videos without effecting my server’s memory consumption ?

  2- Is there a way where I can directly upload the videos on AWS-S3 first, and then use one more proxy server/child application to encode videos from S3, download it to the child server, convert it and again upload it to the destination ? but this is almost the same but doing it on cloud, where memory consumption can be on-demand but will be not cost-effective.

  3- Is there some easy and cost-effective way by which I can upload large videos, transcode them and upload it to AWS S3, without effecting my server memory. Am i missing some technical architecture here.

  4- How Youtube/Netflix works, I know they do the same thing in a smart way but can someone help me to improve this ?

  Thanks in advance.

• Expanding media capabilities of Win Embedded CE 6.0

  1er décembre 2014, par Simo Erkinheimo

  I have an embedded device with WinCE 6.0 as OS. The manufacturer provides an IDE for 3rd party development to it. The IDE pretty much allows nothing else than

  • .NET 3.5 Compact Framework scripting that’s invoked from various events from the main application
  • Adding files to the device.

  The included mediaplayer seems to be using DirectShow and the OS has media codec only for mpeg-1 encoded video playback. My goal is to to be able to play media encoded with some other codecs as well inside that main application.

  I’ve already managed to use DirectShowNETCF (DirectShow wrapper for .NET Compact Framework) and successfully playback mpeg-1 encoded video.

  I’m totally new with this stuff and I have tons of (stupid) questions. I’ll try to narrow them down :

  • The OS is based on WinCE, but as far as I’ve understood, it’s actually always some customized version of it (via Platform Builder). Only "correct way" of developing anything for it afterwards is to use the SDK the manufacturer usually provides. Right ? In my case, the SDK is extremely limited and tightly integrated into IDE as noted above. However, .NET CF 3.5 is capable for interop so its possible to call native libraries -as long as they are compiled for correct platform.

  • Compiled code is pretty much just instructions for the processor (assembler code) and the compiler chooses the correct instructions based on the target processor setting. Also there’s the PE-header that defines under which platform the program is meant to be run. If I target my "helloworld.exe" (does nothing but returns specific exit code) to x86 and compile it with VC, should it work ?

  • If the PE-header is in fact the problem, is it possible to setup for WINCE without the SDK ? Do I REALLY need the whole SDK for creating a simple executable that uses only base types ? I’m using VS2010, which doesn’t even support smart device dev anymore and I’d hate to downgrade just for testing purposes.

  • Above questions are prequel to my actual idea : Porting ffmpeg/ffdshow for WinCE. This actually already exists, but not targeted nor built for Intel Atom. Comments ?

  • If the native implementation is not possible and I would end up implementing some specific codec with C#...well that would probably be quite a massive task. But having to choose C# over native, could I run into problems with codec performance ? I mean.. is C# THAT much slower ?

  Thank you.

• tests/fate/hevc : add a test for selecting view by position

  13 septembre 2024, par Anton Khirnov

  tests/fate/hevc : add a test for selecting view by position
  Using a real-world iPhone-recorded file.
  

  • [DH] tests/fate/hevc.mak
  • [DH] tests/ref/fate/hevc-mv-position