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• How can I use ffmpeg to create a seamless looping gif ? [closed]

  27 juin 2024, par DavidNyan10

  I have an MP4 file which contains animation repeating in a loop. Let's just say, for example, a video of rain. However, when loop is turned on, the video cuts off at the wrong place and does not make a nice smooth animation. The part where it loops is obvious. It's just that the video contains more than one cycle of the loop, but not an exact integer of the full cycle.

  


  My goal is to turn this video into a gif with a seamless loop. In other words, I want the last frame of the video to match the first frame.

  


  My approach : I found a "Seamless loop creator" website on Google, tried it out, and it worked REALLY well. I thought all my problems have been solved. But little did I know, I've been only looking at the few seconds at the beginning and at the end of the video, not paying attention to what's in the middle. The sneaky pesky little website cuts off the video right in the middle, stitch the "seamless transition" at the beginning and end of the video, and put an ugly cross-fade in the middle where the frames don't line up. That is stupid. This of course, isn't noticable on rain videos, but on videos like a character jumping, the crossfade is very visible.

  


  My second approach : I'd use FFMPEG to get the first frame of the video, then starting from the last frame of the video and backwards, it'd try to find a frame that matches exactly with the first frame.

  


  Steps :

  


  

  1. Get the first frame and save it as a PNG or something I don't know

  


  2. Reverse the original video

  


  3. Match the image to each frame of the video in step 2. It is now easier because it's not doing it backwards frame by frame.

  


  4. When a frame match is found, cut off all the frames before this matched frame.

  


  5. Reverse back the video

  


  


  Can I achieve something like this in ffmpeg, preferably a one-liner in windows cmd ?

  


  Follow-up question : Would it be better to leave the last frame the same as first frame or should I remove it ? For example, when it's looping, it would repeat that exact frame two times, is that good ? Or which one provides better results ? And if it's better to not include the last frame (the one that matches), how would I do it in my process above ?

  


  I tried ChatGPT, expecting a ready-made code. Put it in the command prompt and lost my original video file. Had to use a recovery tool because the file was overwritten.

  


• aarch64 : Add Armv8.5-A BTI support

  28 septembre 2020, par Jonathan Wright

  aarch64 : Add Armv8.5-A BTI support
  Add Branch Target Identifiers (BTIs) to all functions defined in
  
  AArch64 assembly files. Most of the BTI landing pads are added
  
  automatically by the 'function' macro.
  BTI support is turned on or off at compile time based on the presence
  
  of the __ARM_FEATURE_BTI_DEFAULT feature macro.
  A binary compiled with BTI support can be executed on an Armv8-A
  
  processor without BTI support because the instructions are defined in
  
  NOP space.
  Signed-off-by : Jonathan Wright <jonathan.wright@arm.com>
  
  Signed-off-by : Elijah Ahmad <elijah.ahmad@arm.com>
  
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DH] libavcodec/aarch64/fft_neon.S
  • [DH] libavcodec/aarch64/h264idct_neon.S
  • [DH] libavutil/aarch64/asm.S

• Problem with extracting audio from a video file (android)

  13 mars 2020, par rom_totach

  I need to convert an mp4 (or any other video format) to mp3 or wav file. I am using C# Xamarin.Forms. Any library I used either doesn’t work for me, or isn’t compatible with android. I have tried using Xamarin.Android.FFMpeg and Xobe.FFMpeg.
  I repost this because it was marked as duplicate and I clearly stated that that solution isn’t working for me. This is the post that was flagged as duplicate : How can I extract the audio out of a video file ? (android) . Please, I tried it but it just gives me the "Downloading Video Converter" dialog with a progress bar when I try to run the code in the solution, Also, it doesn’t even extract the audio so after the user waits such a long time, it turned out as a waste of time.
  Thanks in advance ! :)

  EDIT 1 :

  This is the code I am using :

  private async Task<string> ExtractAudioAsync(string path, Action<string> logger = null,
  
              Action onProgress = null)
  
          {
  
              List<string> cmd = new List<string>();
  
              cmd.Add("-i");
  
              cmd.Add(path + ".mp4");
  
              cmd.Add("-vn");
  
              cmd.Add("-acodec");
  
              cmd.Add("copy");
  
              cmd.Add(path + ".mp3");
  
              string cmdParams = string.Join(' ', cmd);
  
              await FFMpeg.Xamarin.FFMpegLibrary.Run(Context, cmdParams);
  
  
  
              return path + ".mp3";
  
          }
  
  </string></string></string></string>

  There are no exceptions thrown. When the Run method is called it just shows on the application the following dialog :

  

  After that, it just closes the dialog and goes to the return line without even extracting the audio out of the video. Even if I run this code again it does the same thing, downloading it again.

  EDIT 2 :

  I tried adding the -report option but it just did the same thing and did not save any log file. Am I doing something wrong ?