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• Rails 5 - Concurrent large Video uploads using Carrierwave eats up the server memory/space

  22 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.

• Why review compositing work in MJPEG videos rather than (say) H.264 ?

  6 juin 2016, par d3vid

  I have received a request to encode DPX files to MOV/MJPEG rather than MOV/H.264 (which ffmpeg picks by default if you convert to output.mov). These is to review compositing renders (in motion), so color accuracy is critical.

  Comparing a sample "ideal" MOV to the current (H.264) output I can see :

  • resolution : the same
  • ColorSpace/Primaries : Rec609 (SD) versus Rec709 (HD)
  • YUV : 4:2:0 versus 4:4:4
  • filesize : smaller

  The ffmpeg default seems to be better quality and result in a smaller filesize. Is there something I’m missing ?

• HTML5 Video Compatibility (MP4, WEBM, OGG) in 2021

  19 juillet 2021, par William

  The support of HTML5 video has evolved a lot over the years. I am trying to understand whether the <video></video> element still needs to have three sources : MP4, WEBM, and OGG.

  


  There are a lot of answers throughout StackOverflow with deeply conflicting information - some of which say that you just need MP4 now, others say, MP4 and WEBM are enough, and then finally many say that you need all three (although many of those article are 10 years old).

  


  W3 suggests that either MP4 or WEBM alone would have universal support (Even though I found a 2011 article from Google saying that they would be removing support for MP4/H.264). Wikipedia paints a more complicated picture (as well as listing that Google Chrome does indeed support MP4/H.264). Azure Media services ONLY seems to allow output in MP4, which would suggest to me that MP4 must have widespread compatibility.

  


  Also see Example 1, Example 2, Example 3.

  


  Is there any definitive information on what video types to include in an HTML5 video player to achieve widespread compatibility ?

  


  Background : I am building a Content Management Platform that allows uploading videos. When a new video is uploaded, a conversion process kicks off to convert the video into the required formats. This takes time and CPU/Memory, so if it is possible I would like to convert uploaded videos into as few formats as possible.

  


  p.s. This question HAS been asked before, however, the fundamentals of playing video on the web continually evolve and most of the answers out there have become irrelevant.