Recherche avancée

Sur d’autres sites (11888)

• Can I use ffmpeg to output jpegs to a memory stream instead of a file

  1er février 2015, par Andrew Simpson

  I have a c# app. I have 100 jpegs (for an example).

  I can easily encode this into a video file.

  When it has finished encoding on the client app I FTP upload to my server.

  It would be ’neater’ if I could not write the video file to a disc but instead write it to a memory stream (or array of bytes) and upload via web service perhaps ?

  I have checked out the ffmpeg documentation but as a c# developer I do not find it natural to understand the c examples.

  I guess my 1st question is it possible and if so can anyone post me an example code in c# ? At the moment I am using the process class in c# to execute ffmpeg.

  I will of course post this code if it would help ?

  Thanks for everyone’s time.

• What is the difference between raw MediaCodec implementation with FFmpeg integrated MediaCodec ?

  30 avril 2022, par Michael

  I google around the sample code for MediaCodec and notice there are three kinds of implementation in the market :

  


  

  1. Java version

  


  2. NDK version with raw MediaCodec API

  


  3. NDK version but FFmpeg takes care of everything

  


  


  I guess Java version is different on the performance side and use less frequently, but 2 & 3 are very confusing.

  


  If choose option 3, the work is easier and a noticeable change from SW decoding would be avcodec_find_decoder_by_name("h264_mediacodec"), and the implementation can easily share with iOS VideoToolBox.

  


  My question is would it be any performance or device compatible drawbacks compared with raw MediaCodec API ? Why did someone choose to use raw MediaCodec API ?

  


  Plus what if I use surface mode ?

  


• FFMPEG failing in AWS Lambda

  18 février 2019, par Zaid Amir

  I am trying to create a transcoding function for short videos. The function is hosted on AWS Lambda. The problem is that AWS lambda seems to be missing something that FFMPEG requires, at least according to Amazon.

  I contacted Amazon earlier and this is their response to the issue :

  We found that the FFMPEG operations require at least libx264 and an
  acc library, both of which will have dependencies of their own. To
  troubleshoot the issue it will involve diving deeper into the full
  dependency chain. We can see that it works in the Amazon Linux
  environment however, the environment is similar but not identical to
  the lambda environment. There can be some dependencies that exist in
  Amazon Linux but not in lambda environment as Lambda runs on the
  container. Here, as FFmpeg is a third party software, diving deeper
  into the dependency chain and verifying the version compatibilities is
  very hard to do. Unfortunately going further, this is bound to go into
  architecture and code support which is out of AWS Support scope 1. I
  hope you understand our limitations. However should FFmpeg support
  have any questions specific to the Lambda platform, please do let us
  know and we will be happy to assist. We will be in better position to
  investigate further once you receive an update from the FFmpeg support
  suggesting an issue from Lambda end.

  Upon AWS suggestion, I contacted FFMPEG on the developers mailing list, my message was rejected with the reason being that its more suited to ffmpeg users mailing list than developers. I sent an email to ’ffmpeg-user@ffmpeg.org’ a week ago and did not get any response yet.

  I then went and built a dynamically linked ffmpeg version making sure to package all libraries, checked ddl on each one, then made a small lambda function that looped over all binaries and ddled each one of them, compared that to the output I got from Amazon Linux and the same dependencies/versions exists on both lambda and the AWS Linux instance yet ffmpeg still fails on lambda.

  You can find a detailed log file here : https://www.datafilehost.com/d/6e5e21bb

  And this is a sample of the errors I’m getting, repeated across the entire log file :

  2018-08-14T12:27:10.874Z [h264 @ 0x65c2fc0] concealing 2628 DC, 2628
  AC, 2628 MV errors in P frame

  2018-08-14T12:27:10.874Z [aac @ 0x65d2f00] channel element 2.11 is not
  allocated

  2018-08-14T12:27:10.874Z Error while decoding stream #0:1 : Invalid
  data found when processing input

  2018-08-14T12:27:10.874Z [h264 @ 0x67e86c0] Invalid NAL unit size
  (108085662 > 1649).

  2018-08-14T12:27:10.874Z [h264 @ 0x67e86c0] Error splitting the input
  into NAL units.

  2018-08-14T12:27:10.874Z [aac @ 0x65d2f00] channel element 2.0 is not
  allocated

  2018-08-14T12:27:10.874Z Error while decoding stream #0:1 : Invalid
  data found when processing input

  2018-08-14T12:27:10.874Z [h264 @ 0x68189c0] Invalid NAL unit size
  (71106974 > 1085).

  2018-08-14T12:27:10.874Z [h264 @ 0x68189c0] Error splitting the input
  into NAL units.

  2018-08-14T12:27:10.874Z [aac @ 0x65d2f00] Pulse tool not allowed in
  eight short sequence.

  This log is generated when trying to perform an HLS transcoding on this file : https://www.datafilehost.com/d/999a4492

  Note that the issue is not related to that file alone nor is it related to HLS, its general and happen on all videos and any ffmpeg command that tries to seek the stream, even tried extracting a single frame from a video using the simplest form possible for example : ffmpeg -ss 00:00:02 -I file.mp4 -vframes 1 -y output.jpg also fails with the same errors in the log file.

  Not sure how to debug this further. Tried enabling debug logs with ‘-loglevel debug’ but did not give me any extra info. Any help or suggestions