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• How to increase the compression ratio of a JPEG2000 file with "avenc_jpeg2000" GStreamer encoder ?

  10 juillet 2023, par qfr.bertin.group

  I'm using the plugin avenc_jpeg2000, from gst-libav module, combined with videotestsrc and filesink plugins for encoding a raw picture to a JPEG2000 picture :

  


  gst-launch-1.0 videotestsrc num-buffers=1 ! avenc_jpeg2000 ! filesink location=/tmp/picture-ref.jp2


  


  This pipeline works and produce a 31.85 KiB (32,616) file.

  


  Pipeline graph

  


  Now, I want to divide the size of my output file by two by increasing the compression ratio of the encoder avenc_jpeg2000. To achieve this, I want to minimize the number of bits required to represent the image with an allowable level of distortion. I know JPEG2000 standard support lossless and lossy compression mode. For my use case, the lossy compression mode is acceptable.

  


  How should I proceed to increase the compression of my output file ? What encoder's properties should I play with for doing that ?

  


  My test configuration :

  


  


  • i.MX 8M Plus

    


  


  • GStreamer 1.18.0

    


  


  • libav 1.18.0 (Release date : 2020-09-08)

    


  


  


  I tried to play with "bitrate" and "bitrate-tolerance" properties, but it seems to have no effect on the size of the output file :

  


  gst-launch-1.0 videotestsrc num-buffers=1 ! avenc_jpeg2000 bitrate=100000 bitrate-tolerance=10000 ! filesink location=/tmp/picture-test-01.jp2


  


  I compare files by doing a checksum with sha224sum command :

  


  d0da9118a9c93a0420d6d62f104e0d99fe6e50cda5e87a46cef126f9  /tmp/picture-ref.jp2

d0da9118a9c93a0420d6d62f104e0d99fe6e50cda5e87a46cef126f9  /tmp/picture-test-01.jp2


  


• Scale with scale_vaapi and than pad, got error. Seems ok without "pad"

  24 mai 2023, par huangda1982

  My computer : customized Linux, haswell
I am trying to scale 1280x720 video to 640x450 in 640x480 frame with black borders. To do so, I run this command :

  


  ffmpeg -v warning -hide_banner -init_hw_device vaapi=vaapi0:/dev/dri/renderD128 -hwaccel vaapi -hwaccel_output_format vaapi -hwaccel_device vaapi0 -filter_hw_device vaapi0 -i 'my_video.mp4' -vf 'scale_vaapi=640:450,pad=640:480:0:14' -c:v h264_vaapi -q:v 18 -profile:v main -level 3.1 -c:a aac -q:a 3 -f mp4 out.mp4 -loglevel verbose


  


  And I got this error :

  


  Impossible to convert between the formats supported by the filter &#x27;Parsed_scale_vaapi_0&#x27; and the filter &#x27;auto_scaler_0&#x27;<br />&#xA;Error reinitializing filters!&#xA;Failed to inject frame into filter network: Function not implemented&#xA;Error while processing the decoded data for stream #0:0&#xA;

  


  When I removed the ",pad=640:480:0:14" part, the command continued. I pressed ctrl-c, and did not check the result.

  


  "-q:v 18", "-level 3.1" and "-q:a" options seem not work.

  


  Full message :

  


  [h264 @ 0x55dfeb529340] Reinit context to 1280x720, pix_fmt: yuv420p
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'my_video.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: mp41
    creation_time   : 1970-01-01T00:00:00.000000Z
    encoder         : PotEncoder
  Duration: 00:22:45.01, start: 0.000000, bitrate: 3264 kb/s
  Stream #0:0(und): Video: h264 (Constrained Baseline), 1 reference frame (avc1 / 0x31637661), yuv420p(left), 1280x720 [SAR 1:1 DAR 16:9], 3068 kb/s, 23.98 fps, 23.98 tbr, 1199 tbn, 47.96 tbc (default)
    Metadata:
      creation_time   : 1970-01-01T00:00:00.000000Z
      handler_name    : VideoHandler
      vendor_id       : [0][0][0][0]
  Stream #0:1(und): Audio: mp3 (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 192 kb/s (default)
    Metadata:
      creation_time   : 1970-01-01T00:00:00.000000Z
      handler_name    : SoundHandler
      vendor_id       : [0][0][0][0]
File 'out.mp4' already exists. Overwrite? [y/N] y
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> h264 (h264_vaapi))
  Stream #0:1 -> #0:1 (mp3 (mp3float) -> aac (native))
Press [q] to stop, [?] for help
[h264 @ 0x55dfeb553e40] Reinit context to 1280x720, pix_fmt: vaapi_vld
[graph_1_in_0_1 @ 0x55dfeb6b7580] tb:1/44100 samplefmt:fltp samplerate:44100 chlayout:0x3
[graph 0 input from stream 0:0 @ 0x55dfebb4d000] w:1280 h:720 pixfmt:vaapi_vld tb:1/1199 fr:1199/50 sar:1/1
[auto_scaler_0 @ 0x55dfebb4f940] w:iw h:ih flags:'bicubic' interl:0
[Parsed_pad_1 @ 0x55dfebb4c700] auto-inserting filter 'auto_scaler_0' between the filter 'Parsed_scale_vaapi_0' and the filter 'Parsed_pad_1'
Impossible to convert between the formats supported by the filter 'Parsed_scale_vaapi_0' and the filter 'auto_scaler_0'
Error reinitializing filters!
Failed to inject frame into filter network: Function not implemented
Error while processing the decoded data for stream #0:0
[AVIOContext @ 0x55dfeb5522c0] Statistics: 0 seeks, 0 writeouts
[aac @ 0x55dfeb551600] Qavg: 354.000
[aac @ 0x55dfeb551600] 2 frames left in the queue on closing
[AVIOContext @ 0x55dfeb530500] Statistics: 1144787 bytes read, 2 seeks
Conversion failed!


  


• Is there a way to cut movement "dead air" on a screen recording ? [closed]

  16 mai 2023, par Raelbe

  I have got a couple of screen recordings of a painting I've done, and I've managed to concat the files together.

  


  Unfortunately, there is a lot of "dead air" in the video (where I have left my desk, so there is no movement happening on screen) is there a way to cut out this down time ?

  


  I found an example that another artist uses for his screen recordings, so I plugged it in with my file directory's. This is what I used :

  


  .\ffmpeg -f concat -safe 0 -i "merge.txt" -vf npdecimate=hi=64*12:lo=64*5:frac=0.33,seipts=N/30/TB,"setpts=0.25*PTS" -r 30 -crf 30 -an Illu_Test.mp4


  


  I got this error message at the end :

  


  [AVFilterGraph @ 000001cadfe5b1c0] No option name near 'N/30/TB'
[AVFilterGraph @ 000001cadfe5b1c0] Error parsing a filter description around: ,setpts=0.25*PTS
[AVFilterGraph @ 000001cadfe5b1c0] Error parsing filterchain 'npdecimate=hi=64*12:lo=64*5:frac=0.33,seipts=N/30/TB,setpts=0.25*PTS' around: ,setpts=0.25*PTS
Error reinitializing filters!
Failed to inject frame into filter network: Invalid argument
Error while processing the decoded data for stream #0:0`


  


  So I chopped it up a bit and this is what I used to concat the files and it worked perfectly.

  


  .\ffmpeg -f concat -safe 0 -i "merge.txt" -crf 30 -an Illu_Test.mp4


  


  Now, I'm looking to cut out the seconds of no movement. I'm unsure what the -crf command does (as stated I am brand new to this) OG artist states that :

  


  "This is the tolerance level that determines whether there has been enough change between frames or not to be considered as detected motion."

  


  Any help would be appreciated.

  


  (Apologies if the format of this question is wrong)