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• I can't get any error messages on node.js spawn, using ffmpeg

  21 mars 2021, par rickster26ter1

  I am trying to get the errors from a spawn process on nodejs, trying to run FFMPEG. I have not run a child process before explicitly, so I'm not sure this is right, but what I have gathered from code examples online :

  


      const {spawn} = require('child_process');
    async function(req,res){
           
    console.log(res.req.files.data[0].path);
    var tst_loc = res.req.files.data[0].path;
    try {
            var the_arr = tst_loc.split('/');
            the_arr.pop();
            tst_loc1 = the_arr.join('/') +"/test.avi";
            console.log("HERE");
            var cmd = 'ffmpeg';
                var tstspawn = spawn(cmd, [
                '-i', tst_loc,
                '-s', '800x400',
                '-b:v', '64k',
                '-c:v', 'avi',
                '-c:a', tst_loc1,
                '-o', outputfilename
            ], (error, stdout, stderr) => {
                  if (error) {
                      console.error('Error!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!:', stderr);
                      throw error;
                  }
                  console.log('Success!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!', stdout);
            })
            
            tstspawn.stderr.on('data', function(data) {
            //Here is where the error output goes

               console.log('stderr: ' + data);

               data=data.toString();
               scriptOutput+=data;
            });
       

 
            tstspawn.stderr.on('error',function(error){
              console.log(error);
            });

  } catch (e) {
    console.log(e.code);
    console.log(e.msg);
  }


  


  Returns only my console logs of the path data, the console log of the "HERE", and nothing else at all. I know it didn't run properly because I do not get the expected video file that FFMPEG should have output. But I can't get any sort of error message on my console. No crashing of the application or anything...

  


  Thanks for any help,

  


• NumPy array of a video changes from the original after writing into the same video

  29 mars 2021, par Rashiq

  I have a video (test.mkv) that I have converted into a 4D NumPy array - (frame, height, width, color_channel). I have even managed to convert that array back into the same video (test_2.mkv) without altering anything. However, after reading this new, test_2.mkv, back into a new NumPy array, the array of the first video is different from the second video's array i.e. their hashes don't match and the numpy.array_equal() function returns false. I have tried using both python-ffmpeg and scikit-video but cannot get the arrays to match.

  


  Python-ffmpeg attempt :

  


  import ffmpeg
import numpy as np
import hashlib

file_name = 'test.mkv'

# Get video dimensions and framerate
probe = ffmpeg.probe(file_name)
video_stream = next((stream for stream in probe['streams'] if stream['codec_type'] == 'video'), None)
width = int(video_stream['width'])
height = int(video_stream['height'])
frame_rate = video_stream['avg_frame_rate']

# Read video into buffer
out, error = (
    ffmpeg
        .input(file_name, threads=120)
        .output("pipe:", format='rawvideo', pix_fmt='rgb24')
        .run(capture_stdout=True)
)

# Convert video buffer to array
video = (
    np
        .frombuffer(out, np.uint8)
        .reshape([-1, height, width, 3])
)

# Convert array to buffer
video_buffer = (
    np.ndarray
        .flatten(video)
        .tobytes()
)

# Write buffer back into a video
process = (
    ffmpeg
        .input('pipe:', format='rawvideo', s='{}x{}'.format(width, height))
        .output("test_2.mkv", r=frame_rate)
        .overwrite_output()
        .run_async(pipe_stdin=True)
)
process.communicate(input=video_buffer)

# Read the newly written video
out_2, error = (
    ffmpeg
        .input("test_2.mkv", threads=40)
        .output("pipe:", format='rawvideo', pix_fmt='rgb24')
        .run(capture_stdout=True)
)

# Convert new video into array
video_2 = (
    np
        .frombuffer(out_2, np.uint8)
        .reshape([-1, height, width, 3])
)

# Video dimesions change
print(f'{video.shape} vs {video_2.shape}') # (844, 1080, 608, 3) vs (2025, 1080, 608, 3)
print(f'{np.array_equal(video, video_2)}') # False

# Hashes don't match
print(hashlib.sha256(bytes(video_2)).digest()) # b'\x88\x00\xc8\x0ed\x84!\x01\x9e\x08 \xd0U\x9a(\x02\x0b-\xeeA\xecU\xf7\xad0xa\x9e\\\xbck\xc3'
print(hashlib.sha256(bytes(video)).digest()) # b'\x9d\xc1\x07xh\x1b\x04I\xed\x906\xe57\xba\xf3\xf1k\x08\xfa\xf1\xfaM\x9a\xcf\xa9\t8\xf0\xc9\t\xa9\xb7'


  


  Scikit-video attempt :

  


  import skvideo.io as sk
import numpy as np

video_data = sk.vread('test.mkv')

sk.vwrite('test_2_ski.mkv', video_data)

video_data_2 = sk.vread('test_2_ski.mkv')

# Dimensions match but...
print(video_data.shape) # (844, 1080, 608, 3)
print(video_data_2.shape) # (844, 1080, 608, 3)

# ...array elements don't
print(np.array_equal(video_data, video_data_2)) # False

# Hashes don't match either
print(hashlib.sha256(bytes(video_2)).digest()) # b'\x8b?]\x8epD:\xd9B\x14\xc7\xba\xect\x15G\xfaRP\xde\xad&EC\x15\xc3\x07\n{a[\x80'
print(hashlib.sha256(bytes(video)).digest()) # b'\x9d\xc1\x07xh\x1b\x04I\xed\x906\xe57\xba\xf3\xf1k\x08\xfa\xf1\xfaM\x9a\xcf\xa9\t8\xf0\xc9\t\xa9\xb7'


  


  I don't understand where I'm going wrong and both the respective documentations do not highlight how to do this particular task. Any help is appreciated. Thank you.

  


• avcodec/pthread_frame : Fix cleanup during init

  11 février 2021, par Andreas Rheinhardt

  avcodec/pthread_frame : Fix cleanup during init
  In case an error happened when setting up the child threads,
  
  ff_frame_thread_init() would up until now call ff_frame_thread_free()
  
  to clean up all threads set up so far, including the current, not
  
  properly initialized one.
  
  But a half-allocated context needs special handling which
  
  ff_frame_thread_frame_free() doesn't provide.
  
  Notably, if allocating the AVCodecInternal, the codec's private data
  
  or setting the options fails, the codec's close function will be
  
  called (if there is one) ; it will also be called if the codec's init
  
  function fails, regardless of whether the FF_CODEC_CAP_INIT_CLEANUP
  
  is set. This is not supported by all codecs ; in ticket #9099 it led
  
  to a crash.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavcodec/pthread_frame.c