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• Anomalie #4209 : Les critères {pagination} et {a,b} sont dans un bâteau

  30 octobre 2018, par tcharlss (*´_ゝ｀)

  Un exemple concret : un squelette à inclure qui liste des articles, par défaut avec pagination et sans limite du nombre de résultats (en trichant un peu).

  Il est inclus dans plusieurs pages : sur certaines j’ai besoin d’une pagination différente, sur d’autres j’ai besoin de limiter le nombre de résultats.

  liste/articles, pagination=20}>
  
  
  
  
  
  liste/articles, nb=10}>

• Android Exoplayer garbled mp4 video output on imagereader surface while playing fine on SurfaceView (Samsung galaxy tab s7)

  29 mars 2023, par Orcun

  Problem :

  


  I am trying to play an mp4 video file on Samsung Galaxy Tab S7 for video processing purposes. For the purpose, I use Exoplayer(v2.18.4) library to be able to play the video onto an ImageReader surface so that I can grab the frames in ImageReader.OnImageAvailableListener.

  


  I do not have any problems in getting the frames. However, the frames I acquire are garbled/corrupted like :

  


  

  


  When I saw this frame, it made me think that it is some sort of color format or codec issue for the mp4 file or device I use. In logcat, there are no errors reported.
Device uses [OMX.qcom.video.decoder.avc] decoder. Also, same video plays nicely on some other devices that use exactly the same decoder.

  


  What I tried so far :

  


  I tried a lot of things to understand the root cause and also find a solution, so my brain currently is free flowing stream. I will try to summarise, please bear with me.

  


  I use a CustomMediaCodecVideoRenderer in my app which overrides MediaCodecVideoRenderer.getMediaFormat of Exoplayer to set color format like :

  


  setInteger(MediaFormat.KEY_COLOR_FORMAT, MediaCodecInfo.CodecCapabilities.COLOR_FormatYUV420Flexible)


  


  This step proved itself necessary. Without it I get a crash simply because I cannot access the image planes of an image frame in expected YUV image format.
This unfortunately was not enough for the Samsung Galaxy Tab 7 although it was already enough for another device like Xiaomi to render the image correctly.

  


  Then I decided to use a library like ffmpeg to modify the mp4 file itself to maybe use a different profile, color format, resolution that is widely compatible in android devices. No luck so far.
a quick ffprobe on my mp4 file shows :

  


  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'outputyuv169.mp4':
Metadata:
  major_brand     : isom
  minor_version   : 512
  compatible_brands: isomiso2avc1mp41
  encoder         : Lavf59.16.100
Duration: 00:03:00.02, start: 0.000000, bitrate: 4823 kb/s
Stream #0:0[0x1](und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(progressive), 
1280x720 [SAR 1:1 DAR 16:9], 4820 kb/s, 30 fps, 30 tbr, 360k tbn (default)


  


  I tried even recording a simple video on the tablet itself and using that as my input file. Nevertheless, still getting similarly garbled frames.

  


  One thing I keep noticing in logcat is this line :

  


  [OMX.qcom.video.decoder.avc] using color format 0x7fa30c04 in place of 0x7f420888

  


  and

  


  [OMX.qcom.video.decoder.avc] Requested output format 0x7f420888 and got 0x7fa30c04

  


  where 0x7fa30c04 refers to YCbCr_420_SP_VENUS_UBWC. Not really sure If this has anything to do with it. I did not dive too deep into that because same log is present also on other device that renders the mp4 correctly.

  


  I would be grateful for any clue.

  


• Streaming live video from ios [closed]

  15 février 2018, par John

  I have a need to stream video from the iPhone/iPad camera to a server. It looks like this will need to be done with AVCaptureSession but I don’t know how to best architect this.

  I found this post :

  streaming video FROM an iPhone

  But it doesn’t handle the "live" part, latency needs to be 2 or 3 seconds at most. Devices can be constrained to 4 or 4S capability if needed, and there is no requirement for HD, VGA is probably what we’ll end up with. I assume any solution would use ffmpeg, I haven’t found any more appropriate library.

  How is this best accomplished ?