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• How to concatenate two MP4 files, which require http basic Authorization : Bearer , using ffmpeg ?

  8 juillet 2023, par Jeff Strongman

  Hello dear ffmpeg experts ! 🧠 🎯

  


  I ran the following command, which worked perfectly :

  


  ffmpeg -protocol_whitelist https,concat,tls,tcp -i "concat :https://dash.akamaized.net/akamai/bbb_30fps/bbb_30fps_1280x720_4000k/bbb_30fps_1280x720_4000k_0.m4v|https://dash.akamaized.net/akamai/bbb_30fps/bbb_30fps_1280x720_4000k/bbb_30fps_1280x720_4000k_1.m4v|https://dash.akamaized.net/akamai/bbb_30fps/bbb_30fps_1280x720_4000k/bbb_30fps_1280x720_4000k_2.m4v" -c:v copy -vframes 180 -y Movie_of_6_seconds.mp4

  


  I followed the recommended solution of the following post :
How to concatenate two MP4 files using FFmpeg ?

  


  You can execute the command on your local computer and see that it should run just fine...

  


  I used 3. concat protocol, which does indeed concat init + progressive segments

  


  However... when every segment on a server I refer to, is password protected, it fails with 401 Unauthorized, even though I added the following line :
-headers "Authorization : Bearer bas64user:password" , before specifying the -i "concat :...".

  


  It seems to me... that the headers don't pass to the concat command inside of the input of ffmpeg... and it simply ignores them. When I used the same -headers command, on a single file, without concat, it passed the authorization successfully

  


  Notes :

  


  

  • Even though every segment has a length of 120 frames (So in maximum, I could have generated 2*120 = 240 frames... I wanted a movie of 6 seconds and not 8... And by this way, to test that ffmpeg is smart enough to stop processing the whole input). To do that, I used -vframes 180, where 180 / 30 (FPS) = 6 seconds

  


  • I used -c:v copy, to get without re-encoding, only the video part (No audio !)

  


  • I used -y to override existing file...

  


  • 0.m4v, is the init file ! it is a small file, that has metadata of the original video which was produced with mpeg-dash

  


  • 1.m4v and 2.m4v, are the progressive segments

  


  


  Is there a way, to pass the http basic headers (Authorization : Bearer) to all of the chained files ?

  


  Like :

  


  

  • Via a json content type on the ffmpeg request

  


  • Or user:password@video_segment (Although... it seems to me it's not a header ?)

  


  • Somehow specify header inside the concat command ?

  


  


  I don't want to first download all files and then get rid of the password protected... as it both takes ridiculous time & other resources... and I would like to record from a segment that is "endless", meaning a camera that keeps streaming data.

  


  Thanks in advance 🙏🏻,

  


  FFmpeg noobie 🙈

  


• vf_paletteuse : fix color cache lookup for Bayer dithering mode.

  10 janvier 2022, par Rudolf Polzer

  vf_paletteuse : fix color cache lookup for Bayer dithering mode.
  To trigger this bug, use `paletteuse=dither=bayer:bayer_scale=0` ; you will see
  
  that adjacent pixel lines will use the same dither pattern, instead of being
  
  shifted from each other by 32 units (0x20).
  One way to demostrate the bug is :
  $ convert -size 64x256 gradient:black-white -rotate 270 grad.png
  
  $ echo 'P2 2 1 255 0 255' > bw.pnm
  
  $ ffmpeg -i grad.png -filter_complex 'movie=bw.pnm,scale=256x1[bw] ; [0:v][bw]paletteuse=dither=bayer:bayer_scale=0' gradbw.png
  Previously : https://www.rm.cloudns.org/img/uploaded/0bd152c11b9cd99e5945115534b1bdde.png
  
  Now :        https://www.rm.cloudns.org/img/uploaded/89caaa5e36c38bc2c01755b30811f969.png
  This was caused by passing inconsistent color vs (a,r,g,b) parameters to
  
  color_get(), and NBITS being 5 meaning actually hitting the same cache node
  
  does happen in this case, but ONLY if bayer_scale is zero.
  The fix is passing the correct color value to color_get().
  Also added a previous-failing FATE test ; image comparison of the first frame :
  Previously : https://www.rm.cloudns.org/img/uploaded/d0ff9db8d8a7d8a3b8b88bbe92bf5fed.png
  
  Now :        https://www.rm.cloudns.org/img/uploaded/a72389707e719b5cd1c58916a9e79ca8.png
  (on this less synthetic test image, the bug basically causes noise from cache
  
   hits vs misses)
  Tested : FATE passes, which exercises this filter but at the default bayer_scale.
  Reviewed-by : Paul B Mahol <onemda@gmail.com>
  

  • [DH] libavfilter/vf_paletteuse.c
  • [DH] tests/fate/filter-video.mak
  • [DH] tests/ref/fate/filter-paletteuse-bayer0

• Started Programming Young

  6 septembre 2011, par Multimedia Mike — Programming

  I have some of the strangest memories of my struggles to jump into computer programming.

  Back To BASIC
  I remember doing some Logo programming on Apple II computers at school in 5th grade (1987 timeframe). But that was mostly driving turtle graphics. Then I remember doing some TRS-80 BASIC in 7th grade, circa 1989. Emboldened by what very little I had learned in perhaps the week or 2 we took in a science class to do this, I tried a little GW-BASIC on my family’s “IBM-PC compatible” computer (they were still called that back then). I still remember what my first program consisted of. Even back then I was interested in manipulating graphics and color on a computer screen. Thus :

  10 color 1
  20 print "This is color 1"
  30 color 2
  40 print "This is color 2"
  ...
  

  And so on through 15 colors. Hey, it did the job– it demonstrated the 15 different colors you could set in text mode.

  What’s FOR For ?
  That 7th grade computer unit in science class wasn’t very thick on computer science details. I recall working with a lab partner to transcribe code listings into a computer (and also saving my work to a storage cassette). We also developed form processing programs that would print instructions to input text followed by an “INPUT I$” statement to obtain the user’s output.

  I remember there was some situation where we needed a brief delay between input and printing. The teacher told us to use a construct of the form :

  10 FOR I = 1 TO 20000
  20 NEXT I
  

  We had to calibrate the number based on our empirical assessment of how long it lasted but I recall that the number couldn’t be much higher than about 32000, for reasons that would become clearer much later.

  Imagine my confusion when I would read and try to comprehend BASIC program code I would find in magazines. I would of course see that FOR..NEXT construct all over the place but obviously not in the context of introducing deliberate execution delays. Indeed, my understanding of one of the fundamental building blocks of computer programming — iteration — was completely skewed because of this early lesson.

  Refactoring
  Somewhere along the line, I figured out that the FOR..NEXT could be used to do the same thing a bunch of times, possibly with different values. A few years after I had written that color program, I found it again and realized that I could write it as :

  10 for I = 1 to 15
  20 color I
  30 print I
  40 next I
  

  It still took me a few more years to sort out the meaning of WHILE..WEND, though.