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• Output a video file from ffmpeg directly to google cloud storage

  24 juin 2021, par Anup Sedhain

  Background on the problem

  


  We are trying to compress a video using FFmpeg in our server that is hosted in the Google App Engine (GAE). The input file is in Google Cloud Storage (GCS) which can be easily passed as an input to FFmpeg and the processing is done, however, I wanted to output the file directly to GCS. I have referred to the documentation here https://ffmpeg.org/ffmpeg-protocols.html#http that they provided and used the correct headers and method to upload the file using a signed URL, but it doesn't seem to work. As of now, I am not even sure whether this is possible.

  


  Current Implementation

  


  Currently, we are first saving the output file in the GAE workspace and then uploading the file to the bucket. This flow worked fine until we faced another problem. Whenever the file is too big, the processing takes more than 10 mins which seems to be the threshold for Automatically Scaled Instances in the Flexible environment. To get around this problem we could use basic_scaling in a Standard environment but there we cannot seem to write files in the GAE workspace. I could choose to write in the /tmp directory but that uses RAM and we can have many files being uploaded at a time, so it's not an option.

  


  Possible Future

  


  Right now one solution I have seen is to use a Flexible environment with manual scaling, but this is a bad idea when it comes to scaling and cost-effectiveness. Another, which I am not so sure about would be to use Google Compute Engine but I am yet to try this.

  


  Conclusion

  


  The problem that arose from not being able to make a PUT request to Google Cloud Storage from FFmpeg led me to go through tens of problems surrounding GAE and its weird combination of instances and feature set.

  


  Would really appreciate suggestions or possible solutions if I am missing anything. If only we could make the FFmpeg output the file to GCS.

  


• I can’t play HEVC encoded Flv format video files with ffplay

  25 décembre 2023, par 1337zzz

  I could not decode a video file

  


  I have a video file in FLV format. Someone told me that the encoding format of this video is HEVC, so I tried to play this video with ffplay. But I found that native ffplay cannot play HEVC encoded files in flv format, so I found relevant information to decode HEVC encoded files in FLV format, but this file still cannot be played.

  


  The following is the error message, the content is that the NAL part of the analysis failed

  


  [hevc @ 0x7fba4800fc00] Invalid NAL unit size in extradata.
[flv @ 0x7fba4800f000] Could not find codec parameters for stream 0 (Video: hevc, none, 5494 kb/s): unspecified size
Consider increasing the value for the 'analyzeduration' and 'probesize' options



  


  I tried to use ffplay to play other HEVC encoded videos in FLV format, and the result was no problem. So I use a hexadecimal editor to view the file that cannot be played normally. Below is the data of the first frame of video.

  


  000003a0: xx xx xx xx xx xx xx 09 00 00 4E 00 00 00 00 00    ..........N.....
000003b0: 00 00 1E 00 00 00 00 01 00 00 00 FF E2 00 17 40    ............b..@
000003c0: 01 0C 01 FF FF 01 00 01 00 00 B0 00 00 03 00 00    ..........0.....
000003d0: 03 00 96 1D 94 09 00 1E 42 01 01 01 00 01 00 00    ........B.......
000003e0: B0 00 00 03 00 00 03 00 96 A0 01 E0 20 02 1C 5A    0..........`...Z
000003f0: 1D 96 49 0A 40 A2 01 00 07 44 01 C0 13 18 21 20    ..I.@"...D.@..!.


  


  We can see that 09 represents the video type, 4E represents the length of TAG data, and 1C represents the key frame of HEVC, but I can’t judge whether the following data is HEVC encoded data, so I suspect that the latter data may not be encoded by HEVC.

  


  Question

  


  Is there any way to detect the encoding format of the video based on the hexadecimal data, or who can tell me which video encoding format the following data is ?

  


  Thank you very much !

  


• avformat/dashenc : addition of segment index correction logic

  11 avril 2018, par Vishwanath Dixit

  avformat/dashenc : addition of segment index correction logic
  The logic is applicable only when use_template is enabled and use_timeline
  
  is disabled. The logic monitors the flow of segment indexes. If a streams's
  
  segment index value is not at the expected real time position, then
  
  the logic corrects that index value.
  Typically this logic is needed in live streaming use cases. The network
  
  bandwidth fluctuations are common during long run streaming. Each
  
  fluctuation can cause the segment indexes fall behind the expected real
  
  time position. Without this logic, players will not be able to consume
  
  the content, even after encoder's network condition comes back to
  
  normal state.
  

  • [DH] doc/muxers.texi
  • [DH] libavformat/dashenc.c