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• MoviePy write_videofile is very slow. Why ?

  5 novembre 2024, par RukshanJS

  I've seen multiple questions on SO relating with this, but couldn't find a solid answer. The following is my code.

  


  async def write_final_video(clip, output_path, results_dir):
    cpu_count = psutil.cpu_count(logical=False)
    threads = max(1, min(cpu_count - 1, 16))

    os.makedirs(results_dir, exist_ok=True)

    output_params = {
        "codec": await detect_hardware_encoder(),
        "audio_codec": "aac",
        "fps": 24,
        "threads": threads,
        "preset": "medium",
        "bitrate": "5000k",
        "audio_bitrate": "192k",
    }

    logger.info(f"Starting video writing process with codec: {output_params['codec']}")
    try:
        await asyncio.to_thread(
            clip.write_videofile,
            output_path,
            **output_params,
        )
    except Exception as e:
        logger.error(f"Error during video writing with {output_params['codec']}: {str(e)}")
        logger.info("Falling back to libx264 software encoding")
        output_params["codec"] = "libx264"
        output_params["preset"] = "medium"
        try:
            await asyncio.to_thread(
                clip.write_videofile,
                output_path,
                **output_params,
            )
        except Exception as e:
            logger.error(f"Error during fallback video writing: {str(e)}")
            raise
    finally:
        logger.info("Video writing process completed")

    # Calculate and return the relative path
    relative_path = os.path.relpath(output_path, start=os.path.dirname(ARTIFACTS_DIR))
    return relative_path


  


  and the helper function to get encoder is below

  


  async def detect_hardware_encoder():
    try:
        result = await asyncio.to_thread(
            subprocess.run,
            ["ffmpeg", "-encoders"],
            capture_output=True,
            text=True
        )

        # Check for hardware encoders in order of preference
        if "h264_videotoolbox" in result.stdout:
            return "h264_videotoolbox"
        elif "h264_nvenc" in result.stdout:
            return "h264_nvenc"
        elif "h264_qsv" in result.stdout:
            return "h264_qsv"

        return "libx264"  # Default software encoder
    except Exception:
        logger.warning("Failed to check for hardware acceleration. Using default encoder.")
        return "libx264"


  


  This code makes the rendering of a 15s video around 6min+ which is not acceptable.

  


  t:  62%|██████▏   | 223/361 [04:40<03:57,  1.72s/it, now=None]

  


  My config is MPS (Apple Silicon Metal Performance Shader), but also should work with NVIDIA CUDA.

  


  How can I reduce the time to write the video ? How to actually reduce this long time to write the file ?

  


  The question is about optimizing MoviePy's video processing pipeline, not just FFmpeg :

  


  

  1. clip is a MoviePy VideoFileClip object handling video processing before FFmpeg encoding

  


  2. write_videofile() is MoviePy's method that manages the entire rendering pipeline including :

     

     • Frame extraction and processing

     


     • Memory management

     


     • Multiprocessing coordination

     


     • Audio synchronization

     


     


  


  


  Source - https://zulko.github.io/moviepy/getting_started/videoclips.html#video-files-mp4-webm-ogv

  


  Other places where this is asked,

  


  

  • https://github.com/Zulko/moviepy/issues/2039

  


  


• ffmpeg progess bar not giving percent

  3 décembre 2014, par Brett

  Hi im trying to create a java program that shows the percent of a ffmpeg command , Im not sure where i am going wrong.

  Its keeps giving me these results

  run :
  Total duration : 857.44 seconds.
  Progress : 0.85%
  Progress : 1.76%
  Progress : 2.79%
  Progress : 3.93%
  Progress : 5.04%
  Progress : 6.21%
  Progress : 6000.27%
  Progress : 6001.29%
  Progress : 6002.46%
  Progress : 6003.58%
  Progress : 6004.59%
  Progress : 6005.70%
  Progress : 6006.77%
  Progress : 12000.86%
  Progress : 12001.97%
  Progress : 12002.97%
  Progress : 12004.03%
  Progress : 12005.15%
  Progress : 12006.27%
  Progress : 18000.34%
  Progress : 18001.46%
  Progress : 18002.29%
  Progress : 18003.41%
  Progress : 18004.41%
  Progress : 18005.50%
  Progress : 18006.55%
  Progress : 24000.52%
  Progress : 24001.62%
  Progress : 24002.74%
  Progress : 24003.69%
  Progress : 24004.76%
  Progress : 24005.88%
  Progress : 24006.94%
  Progress : 30001.01%
  Progress : 30002.16%
  Progress : 30003.24%
  Progress : 30004.25%
  Progress : 30005.37%
  Progress : 30006.44%
  Progress : 36000.56%
  Progress : 36001.60%
  Progress : 36002.69%
  Progress : 36003.73%
  Progress : 36004.81%
  Progress : 36005.93%
  Progress : 42000.05%
  Progress : 42001.18%
  Progress : 42002.30%
  Progress : 42003.41%
  Progress : 42004.50%
  Progress : 42005.60%
  Progress : 42006.72%
  Progress : 48000.84%
  Progress : 48001.96%
  Progress : 48003.08%
  Progress : 48004.18%
  Progress : 48005.09%
  Progress : 48006.16%
  Progress : 54000.22%
  Progress : 54001.15%
  Progress : 54002.20%
  Progress : 54003.30%
  Progress : 54004.42%
  Progress : 54005.49%
  Progress : 54006.38%
  Progress : 60000.45%
  Progress : 60001.57%
  Progress : 60002.55%
  Progress : 60003.64%
  Progress : 60004.66%
  Progress : 60005.62%
  Progress : 60006.72%
  Progress : 66000.67%
  Progress : 66001.73%
  Progress : 66002.75%
  Progress : 66003.61%
  Progress : 66004.71%
  Progress : 66005.82%
  Progress : 66006.81%
  Progress : 72000.67%
  Progress : 72001.73%
  Progress : 72002.80%
  Progress : 72003.87%
  Progress : 72004.81%
  Progress : 72005.71%
  Progress : 72006.69%
  Progress : 78000.73%
  Progress : 78001.82%
  Progress : 78002.91%
  Progress : 78003.91%
  Progress : 78004.98%
  Progress : 78005.88%
  Progress : 78006.49%
  Progress : 84000.37%
  Progress : 84001.12%
  Progress : 84002.04%
  BUILD SUCCESSFUL (total time : 49 seconds)

  But the file is created , i don’t know why im getting 0.00% any help would be awsome
  ..
  It also complains some imports a not being used here are the imports.

  here is my code

  import java.io.IOException;
  
  import java.util.Scanner;
  
  import static java.util.logging.Level.parse;
  
  import java.util.regex.Pattern;
  
  import javafx.util.Duration;
  
  import static javax.management.Query.lt;
  
  /**
  
   *
  
   * @author brett
  
   */
  
  
  
  public class MashMeUp {
  
  
  
      public static void main(String[] args) throws IOException {
  
          ProcessBuilder pb = new ProcessBuilder("ffmpeg", "-i", "C:\\Users\\brett\\Documents\\Telegraph_Road.mp4", "C:\\Users\\brett\\Documents\\out.mp4");
  
  
  
          // ProcessBuilder pb = new ProcessBuilder(args);  
  
          final Process p = pb.start();
  
  
  
      // create a new thread to get progress from ffmpeg command , override  
  
          // it's run method, and start it!  
  
          new Thread() {
  
              public void run() {
  
  
  
                  Scanner sc = new Scanner(p.getErrorStream());
  
  
  
                  // Find duration  
  
                  Pattern durPattern = Pattern.compile("(?<=Duration: )[^,]*");
  
                  String dur = sc.findWithinHorizon(durPattern, 0);
  
                  if (dur == null) {
  
                      throw new RuntimeException("Could not parse duration.");
  
                  }
  
                  String[] hms = dur.split(":");
  
                  double totalSecs = Integer.parseInt(hms[0]) * 3600
  
                          + Integer.parseInt(hms[1]) * 60
  
                          + Double.parseDouble(hms[2]);
  
                  System.out.println("Total duration: " + totalSecs + " seconds.");
  
  
  
                  // Find time as long as possible.  
  
                  Pattern timePattern = Pattern.compile("(?<=time=)[\\d:.]*");
  
                  // TODO make regex that works with ffmpeg static build  
  
                  String match;
  
                  String[] matchSplit;
  
  while (null != (match = sc.findWithinHorizon(timePattern, 0))) {
  
      matchSplit = match.split(":");
  
      double progress = Double.parseDouble(matchSplit[2]) / totalSecs +  Integer.parseInt(matchSplit[0]) * 3600 + Integer.parseInt(matchSplit[1]) * 60;
  
                      System.out.printf("Progress: %.2f%%%n", progress * 100);
  
                  }
  
              }
  
          }.start();
  
      }
  
  }

• lavu/tx : implement aarch64 NEON SIMD FFT

  3 février 2022, par Lynne

  lavu/tx : implement aarch64 NEON SIMD FFT
  The fastest fast Fourier transform in not just the west, but the world,
  
  now for the most popular toy ISA.
  On a high level, it follows the design of the AVX2 version closely,
  
  with the exception that the input is slightly less permuted as we don't have
  
  to do lane switching with the input on double 4pt and 8pt.
  On a low level, the lack of subadd/addsub instructions REALLY penalizes
  
  any attempt at writing an FFT. That single register matters a lot,
  
  and reloading it simply takes unacceptably long.
  
  In x86 land, vendors would've noticed developers need this.
  
  In ARM land, you get a badly designed complex multiplication instruction
  
  we cannot use, that's not present on 95% of devices. Because only
  
  compilers matter, right ?
  Future optimization options are very few, perhaps better register
  
  management to use more ld1/st1s.
  All timings below are in cycles :
  
  A53 :
  
  Length | C           | New (lavu)  | Old (lavc)  | FFTW
  
   |-------------|-------------|-------------|-----
  
  4      |         842 | 420         | 1210        | 1460
  
  8      |        1538 | 1020        | 1850        | 2520
  
  16     |        3717 | 1900        | 3700        | 3990
  
  32     |        9156 | 4070        | 8289        | 8860
  
  64     |       21160 | 9931        | 18600       | 19625
  
  128    |       49180 | 23278       | 41922       | 41922
  
  256    |      112073 | 53876       | 93202       | 101092
  
  512    |      252864 | 122884      | 205897      | 207868
  
  1024   |      560512 | 278322      | 458071      | 453053
  
  2048   |     1295402 | 775835      | 1038205     | 1020265
  
  4096   |     3281263 | 2021221     | 2409718     | 2577554
  
  8192   |     8577845 | 4780526     | 5673041     | 6802722
  Apple M1
  
  New  - Total for len 512 reps 2097152 = 1.459141 s
  
  Old  - Total for len 512 reps 2097152 = 2.251344 s
  
  FFTW - Total for len 512 reps 2097152 = 1.868429 s
  New  - Total for len 1024 reps 4194304 = 6.490080 s
  
  Old  - Total for len 1024 reps 4194304 = 9.604949 s
  
  FFTW - Total for len 1024 reps 4194304 = 7.889281 s
  New  - Total for len 16384 reps 262144 = 10.374001 s
  
  Old  - Total for len 16384 reps 262144 = 15.266713 s
  
  FFTW - Total for len 16384 reps 262144 = 12.341745 s
  New  - Total for len 65536 reps 8192 = 1.769812 s
  
  Old  - Total for len 65536 reps 8192 = 4.209413 s
  
  FFTW - Total for len 65536 reps 8192 = 3.012365 s
  New  - Total for len 131072 reps 4096 = 1.942836 s
  
  Old  - Segfaults
  
  FFTW - Total for len 131072 reps 4096 = 3.713713 s
  Thanks to wbs for some simplifications, assembler fixes and a review
  
  and to jannau for giving it a look.
  

  • [DH] libavutil/aarch64/Makefile
  • [DH] libavutil/aarch64/tx_float_init.c
  • [DH] libavutil/aarch64/tx_float_neon.S
  • [DH] libavutil/tx.c
  • [DH] libavutil/tx_priv.h