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• How to benchmark x264 in ARM9 environment

  8 mars 2020, par curious_beast

  1.How to benchmark x264 video encoder in Dual-core ARM Cortex™-A9 ?.
  2.How to calculate the encoding speed with respect to the CPU clock frequency ?.

• How to benchmark x264 in ARM9 environment

  16 mars 2020, par curious_beast

  1.How to benchmark x264 video encoder in Dual-core ARM Cortex™-A9 ?.
2.How to calculate the encoding speed with respect to the CPU clock frequency ?.
3.Is h.264 lossless codec ?.

  


• ffmpeg takes a while to start

  17 octobre 2020, par Suspended

  I have this command in python script, in a loop :

  


  ffmpeg -i somefile.mp4 -ss 00:03:12 -t 00:00:35 piece.mp4 -loglevel error -stats


  


  It cuts out pieces of input file (-i). Input filename, as well as start time (-ss) and length of the piece I cut out (-t) varies, so it reads number of mp4 files and cuts out number of pieces from each one. During execution of the script it might be called around 100 times. My problem is that each time before it starts, there is a delay of few seconds and it adds up to significant time. How can I get it to start immediately ?

  


  The script (process_videos.py) :
  

  


  import subprocess
import sys
import math
import time

class TF:
    """TimeFormatter class (TF).
This class' reason for being is to convert time in short
form, e.g. 1:33, 0:32, or 23 into long form accepted by
mp4cut function in bash, e.g. 00:01:22, 00:00:32, etc"""

def toLong(self, shrt):
    """Converts time to its long form"""
    sx = '00:00:00'
    ladd = 8 - len(shrt)
    n = sx[:ladd] + shrt
    return n

def toShort(self, lng):
    """Converts time to short form"""
    if lng[0] == '0' or lng[0] == ':':
        return self.toShort(lng[1:])
    else:
        return lng

def toSeconds(self, any_time):
    """Converts time to seconds"""
    if len(any_time) < 3:
        return int(any_time)
    tt = any_time.split(':')
    if len(any_time) < 6:            
        return int(tt[0])*60 + int(tt[1])
    return int(tt[0])*3600 + int(tt[1])*60 + int(tt[2])

def toTime(self, secsInt):
    """"""
    tStr = ''
    hrs, mins, secs = 0, 0, 0
    if secsInt >= 3600:
        hrs = math.floor(secsInt / 3600)
        secsInt = secsInt % 3600
    if secsInt >= 60:
        mins = math.floor(secsInt / 60)
        secsInt = secsInt % 60
    secs = secsInt
    return str(hrs).zfill(2) + ':' + str(mins).zfill(2) + ':' + str(secs).zfill(2)

def minus(self, t_start, t_end):
    """"""
    t_e = self.toSeconds(t_end)
    t_s = self.toSeconds(t_start)
    t_r = t_e - t_s
    hrs, mins, secs = 0, 0, 0
    if t_r >= 3600:
        hrs = math.floor(t_r / 3600)
        t_r = t_r - (hrs * 3600)
    if t_r >= 60:
        mins = math.floor(t_r / 60)
        t_r = t_r - (mins * 60)
    secs = t_r
    hrsf = str(hrs).zfill(2)
    minsf = str(mins).zfill(2)
    secsf = str(secs).zfill(2)
    t_fnl = hrsf + ':' + minsf + ':' + secsf
    return t_fnl

def go_main():
    tf = TF()
    vid_n = 0
    arglen = len(sys.argv)
    if arglen == 2:
        with open(sys.argv[1], 'r') as f_in:
            lines = f_in.readlines()
            start = None
            end = None
            cnt = 0
            for line in lines:
                if line[:5] == 'BEGIN':
                    start = cnt
                if line[:3] == 'END':
                    end = cnt
                cnt += 1
            if start == None or end == None:
                print('Invalid file format. start = {}, end = {}'.format(start,end))
                return
            else:
                lines_r = lines[start+1:end]
                del lines
                print('videos to process: {}'.format(len(lines_r)))
                f_out_prefix = ""
                for vid in lines_r:
                     vid_n += 1
                    print('\nProcessing video {}/{}'.format(vid_n, len(lines_r)))
                    f_out_prefix = 'v' + str(vid_n) + '-'
                    dat = vid.split('!')[1:3]
                    title = dat[0]
                    dat_t = dat[1].split(',')
                    v_pieces = len(dat_t)
                    piece_n = 0
                    video_pieces = []
                    cmd1 = "echo -n \"\" > tmpfile"
                    subprocess.run(cmd1, shell=True)                    
                    print('  new tmpfile created')
                    for v_times in dat_t:
                        piece_n += 1
                        f_out = f_out_prefix + str(piece_n) + '.mp4'
                        video_pieces.append(f_out)
                        print('  piece filename {} added to video_pieces list'.format(f_out))
                        v_times_spl = v_times.split('-')
                        v_times_start = v_times_spl[0]
                        v_times_end = v_times_spl[1]
                        t_st = tf.toLong(v_times_start)
                        t_dur = tf.toTime(tf.toSeconds(v_times_end) - tf.toSeconds(v_times_start))
                        cmd3 = ["ffmpeg", "-i", title, "-ss", t_st, "-t", t_dur, f_out, "-loglevel", "error", "-stats"]
                        print('  cutting out piece {}/{} - {}'.format(piece_n, len(dat_t), t_dur))
                        subprocess.run(cmd3)
                    for video_piece_name in video_pieces:
                        cmd4 = "echo \"file " + video_piece_name + "\" >> tmpfile"
                        subprocess.run(cmd4, shell=True)
                        print('  filename {} added to tmpfile'.format(video_piece_name))
                    vname = f_out_prefix[:-1] + ".mp4"
                    print('  name of joined file: {}'.format(vname))
                    cmd5 = "ffmpeg -f concat -safe 0 -i tmpfile -c copy joined.mp4 -loglevel error -stats"
                    to_be_joined = " ".join(video_pieces)
                    print('  joining...')
                    join_cmd = subprocess.Popen(cmd5, shell=True)
                    join_cmd.wait()
                    print('  joined!')
                    cmd6 = "mv joined.mp4 " + vname
                    rename_cmd = subprocess.Popen(cmd6, shell=True)
                    rename_cmd.wait()
                    print('  File joined.mp4 renamed to {}'.format(vname))
                    cmd7 = "rm " + to_be_joined
                    rm_cmd = subprocess.Popen(cmd7, shell=True)
                    rm_cmd.wait()
                    print('rm command completed - pieces removed')
                cmd8 = "rm tmpfile"
                subprocess.run(cmd8, shell=True)
                print('tmpfile removed')
                print('All done')
    else:
        print('Incorrect number of arguments')

############################
if __name__ == '__main__':
    go_main()


  


  process_videos.py is called from bash terminal like this :

  


  $ python process_videos.py video_data   


  


  video_data file has the following format :

  


  BEGIN
!first_video.mp4!3-23,55-1:34,2:01-3:15,3:34-3:44!
!second_video.mp4!2-7,12-44,1:03-1:33!
END


  


  My system details :

  


  System:    Host: snowflake Kernel: 5.4.0-52-generic x86_64 bits: 64 Desktop: Gnome 3.28.4
           Distro: Ubuntu 18.04.5 LTS
Machine:   Device: desktop System: Gigabyte product: N/A serial: N/A
Mobo:      Gigabyte model: Z77-D3H v: x.x serial: N/A BIOS: American Megatrends v: F14 date: 05/31/2012
CPU:       Quad core Intel Core i5-3570 (-MCP-) cache: 6144 KB 
           clock speeds: max: 3800 MHz 1: 1601 MHz 2: 1601 MHz 3: 1601 MHz 4: 1602 MHz
Drives:    HDD Total Size: 1060.2GB (55.2% used)
           ID-1: /dev/sda model: ST31000524AS size: 1000.2GB
           ID-2: /dev/sdb model: Corsair_Force_GT size: 60.0GB
Partition: ID-1: / size: 366G used: 282G (82%) fs: ext4 dev: /dev/sda1
           ID-2: swap-1 size: 0.70GB used: 0.00GB (0%) fs: swap dev: /dev/sda5
Info:      Processes: 313 Uptime: 16:37 Memory: 3421.4/15906.9MB Client: Shell (bash) inxi: 2.3.56