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• FFMPEG - Correct command line parameters to create a H.264 Streaming MP4 from a set of images

  27 septembre 2021, par Adam

  I have no problems viewing a video created by my current parameters in a HTML5 browser, Flash player, Windows Phone 7, Android Phone, etc. However, they won't display on iPhone or iPad. If I modify the video using Super and select "Enable Streaming" checkbox they work on iPhone and iPad suddenly. We are suspecting that my command line parameters are incorrect for enabling h.264 streaming and are instead generating a "progressive download" video.

  



  I'm pretty new to FFMPEG and don't understand a lot of the parameters. Can anyone help correct my existing parameters, or maybe provide the missing parameters, etc ?

  



  Thanks in advance.

  



  My current FFMPEG command line paramters are :

  



  ffmpeg.exe 
 -r 30 
 -threads 4 
 -f image2 
 -i .\frame%05d.jpg 
 -i audioFile  
 -acodec aac 
 -ab 128k 
 -ar 44100
 -vcodec h264 
 -crf 27 
 -coder 1 
 -flags +loop 
 -cmp +chroma 
 -partitions +parti4x4+partp8x8+partb8x8 
 -me hex 
 -subq 5 
 -me_range 16 
 -g 60 
 -keyint_min 25 
 -sc_threshold 40 
 -i_qfactor 0.71 
 -b_strategy 1 
 out.mp4


  


• Preprocessing of Columbia active speaker dataset

  21 octobre 2019, par aspit794

  I would like to use the Columbia dataset (which is 1 video https://youtu.be/6GzxbrO0DHM) and its ground truth annotation (http://www.jaychakravarty.com/wp-content/uploads/2016/02/columbiaDatasetGroundTruth.zip).

  annotation contain the frame_id (int), x and y position of the bounding box (int, int), the width=height of the bounding box (int), and the ground truth for active speaker (0 or 1)

  More information : https://www.jaychakravarty.com/active-speaker-detection/

  I managed to download the video, extracted the frames with

  ffmpeg -loglevel 0 -i columbia.mkv columbia/frame_%06d.jpg -nostdin -vf -an -hide_banner

  and draw the ground truth bounding boxes to the video frames (where available).

  However, the bounding boxes are not in the correct places, and I am a bit helpless.

  I tried to convert the video to other frame rate (e.g. 25 fps), but the annotation is not fit.

  I read every paper available, which is related to this dataset, but neither of them mention any information about preprocessing, and the codebase is not publicly available.

  How should I preprocess the video to interpret the annotation ?

• Playing encrypted m4a on Android

  20 novembre 2013, par Fixee

  I'm pulling down encrypted music, decrypting on-the-fly to m4a plaintext buffer and want to then play this music on Android (4.x). It appears the options are bleak :

  1. Write the buffer to disk and use MediaPlayer() with a FileDescriptor
  2. Write the buffer to disk and use a proxy like nano to serve MediaPlayer() via a URI
  3. Decode the buffer to PCM and use AudioTrack to play it

  Options 1 and 2 require writing plaintext to SD, which isn't acceptable. Option 3 requires decoding in software (with, eg, ffmpeg) which seems ridiculous : if there are hardware decoders on the device we can't use them. And if there is a software decoder, we can't access it and put yet another decoder on the device (ffmpeg's).

  Note that using OpenSL doesn't help at all : you still cannot play m4a's from a buffer. Is there another way ?