Recherche avancée

Sur d’autres sites (10427)

• speeding up x264 encoding (C++ code with libavcodec)

  20 décembre 2012, par Hrishikesh_Pardeshi

  I am trying to capture windows screen (continuous screen shots) and encode them into x264. For that I am using avcodec_encode_video2 function available with libavcodec. However, it takes a huge amount of time. The time fluctuates between 25 – 1800 milliseconds for encoding individual frames.

  I tried tried both 1080p and 720p with video recording on screen.

  These are the settings I am using. This was tested on Windows 7, win32 release build with 4 GB of RAM.

  bit_rate = 2000, width = 1920, height = 1080
  qmin = 0, qmax = 0, max_b_frames = 0, frame_rate = 25, pixel_format = YUV 4:4:4.
  The remaining settings are default which are fetched using avcodec_get_context_defaults3().

  Sample data(in milliseconds) for 20 frames (consecutive and chosen randomly) in a set of 250 frames.
  121, 106, 289, 126, 211, 30, 181, 58, 213, 34, 245, 50, 56, 364, 247, 171, 254, 83, 82, 229

  For the application it is a must that it captures at least at 15 fps. Can someone help out to tell whether any options can be used to improve the frame rate. I need to encode lossless, but I am open to some file size increase.

  Thanks in advance.

• FFmpeg : Pipe segments to s3

  24 septembre 2024, par Brendan Kennedy

  I'd like to pipe ffmpeg segments to s3 without writing them to disk.

  


  ffmpeg -i t2.mp4 -map 0 -c copy -f segment -segment_time 20 output_%04d.mkv


  


  Is it possible to modify this command so that ffmpeg writes segments to an s3 bucket ? Something like this perhaps ?

  


  ffmpeg -i t2.mp4 -map 0 -c copy -f segment -segment_time 20 pipe:1 \
  | aws s3 cp - s3://bucket/output_%04d.mkv


  


  When I run the command above I receive this error

  


  Could not write header for output file #0
(incorrect codec parameters ?): Muxer not found


  


  This command works except the entire video is uploaded and not the individual segments

  


  ffmpeg -i t2.mp4 -map 0 -c copy -f segment -segment_time 20 pipe:output_%04d.mkv \
| aws s3 cp - s3://bucket/test.mkv


  


• avfoundation : Fix compilation for OSes other than macOS and iOS

  25 mars, par Martin Storsjö

  avfoundation : Fix compilation for OSes other than macOS and iOS
  E.g. tvOS doesn't have devicesWithMediaType.
  In principle, we could probably disable building the whole
  
  input device on such OSes, but that would either require
  
  testing explicitly for the OS type in configure (which we don't
  
  do anywhere so far), or test for individual objective C methods.
  This approach allows the code to compile, but no input devices
  
  will be found at runtime.
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DH] libavdevice/avfoundation.m