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• Merge commit '0c0b87f12d48d4e7f0d3d13f9345e828a3a5ea32'

  28 septembre 2017, par James Almer

  Merge commit '0c0b87f12d48d4e7f0d3d13f9345e828a3a5ea32'
  * commit '0c0b87f12d48d4e7f0d3d13f9345e828a3a5ea32' :
  
    aarch64 : vp9itxfm : Fix incorrect vertical alignment
  
    aarch64 : vp9itxfm : Update a comment to refer to a register with a different name
  
    aarch64 : vp9itxfm : Use the right lane sizes in 8x8 for improved readability
  
    aarch64 : vp9itxfm : Use a single lane ld1 instead of ld1r where possible
  
    aarch64 : vp9itxfm : Share instructions for loading idct coeffs in the 8x8 function
  
    arm : vp9itxfm : Share instructions for loading idct coeffs in the 8x8 function
  
    aarch64 : vp9itxfm : Do separate functions for half/quarter idct16 and idct32
  
    arm : vp9itxfm : Do a simpler half/quarter idct16/idct32 when possible
  
    aarch64 : vp9itxfm : Move the load_add_store macro out from the itxfm16 pass2 function
  
    arm : vp9itxfm : Move the load_add_store macro out from the itxfm16 pass2 function
  
    aarch64 : vp9itxfm : Make the larger core transforms standalone functions
  
    arm : vp9itxfm : Make the larger core transforms standalone functions
  This commit is a noop, see
  
  f8fcee0daf42d16581ec581bd5ff6373c3a76103
  
  dc47bf3872fde18f6aea33f015a95b70e24dff19
  
  3bd9b39108076e1fca8cd26970cb946fce66523a
  
  a681c793a30386d01d273ce86b3368311cffb511
  
  824589556cb7c4bfafb8a0190e71a10c628f5339
  
  9532a7d4d060f2a2741225a76945daed52dbc478
  
  1d8ab576a7e40ea6209dd753929f26dcb37e1444
  
  3006e5253afc6a0ee001916806aae80f157d7043
  
  19a0f9529ccdb48696f0caa251fe36b1d30df739
  
  6752318c737663f0ac019de3acd63e3cea706864
  
  d0fbf7f34e7243f6a4cbde9925f34d924e6d93f7
  
  16ef000799b227d0226b7a678d28c34ff1d09410
  Merged-by : James Almer <jamrial@gmail.com>
  

• ffplay - how to have video and audio waveform [duplicate]

  19 février 2018, par francis

  This question already has an answer here :

  • ffplay / ffmpeg setup table with audio and video filters
    
    1 answer
    

  I’ve been trying out various commands trying to figure out how to have a stack of video and audio waveform according to : https://trac.ffmpeg.org/wiki/FancyFilteringExamples#waveform

  Video only :

  ffplay -i abc.mp4 -vf "split[a][b];[a]waveform=e=1,split=1[c];[c]crop=in_w:16:0:0,lutyuv=y=val:v=180[high]; [b][high]vstack=2"

  Audio only :

  ffplay -f lavfi 'amovie=april.flac,asplit=2[out1][a]; [a]showwaves=s=640x240[waves]; [waves] vstack[out0]'

  But there isn’t any that combines and shows the top half as video and bottom half as the audio waveform. Is it possible ?

• A 'clean' way to cut an MP4 movie into two sections using FFMPEG ?

  30 août 2020, par Peter in Japan

  I am attempting to use FFMPEG to make a script that can easily split a short MP4 movie with sound into two pieces at a certain point. I've searched through what feels like hundreds of posts to try to find "the" answer, but most of my attempts end up with poor results, broken video files that cause my video play to freeze, and so on. I am attempting to make a script that allows me to easily cut a short anime movie (something grabbed from Twitter or some other short source) and cut it into two sections, so it can be under the 2:20 Twitter time limit, or to cut out some scene I don't want to show my followers.

  


  The issue is that FFMPEG is good at cutting videos into segments, but bad at know where keyframes are, so most videos have two seconds of blank video at the front before some keyframe appears, which looks terrible.

  


  One example I found that works well is below, which cuts any mp4 into a bunch of chunks of n second size (six seconds in the example below). Source and documentation for this is https://moe.vg/3b8eNTs

  


  ffmpeg -i seitokai.mp4 -c:v libx264 -crf 22 -map 0 -segment_time 6 -reset_timestamps 1 -g 30 -sc_threshold 0 -force_key_frames "expr:gte(t,n_forced*1)" -f segment output%03d.mp4

  


  This code works great, at least allowing me to access the "left" side of a video that I want, in this case a six-second segment I want. Can anyone tell me how to accomplish the above, but starting at the 13-second period in said video, so I could get right "right" (not starting from 00:00:00) video cut cleanly ?

  


  Alternately, a single, unified and elegant way to split (re-encode) an MP4 into two segments that forces keyframes from the very beginning of the cut pieces would be wonderful. I can't believe how hard this seems to be.

  


  Thanks in advance for any help you can give ! Greetings from rural Japan !