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• ffmpeg - MXF with 4-channel audio : how to create proxies (high quality / small file size) and preserve the audio mapping

  8 juillet 2018, par WhatsYourFunction

  We’ve got MXF sources (h.264 video at UHD (3840x2160) with 4-channels of (4 - PCM S24 mono sources)
  We want Proxies — smallest file size at highest picture quality
  The compression applied to the video and audio essences can be anything,
  And the wrapper can be either MXF or QuickTime
  but we need to preserve the audio mapping (i.e. the Proxy must be 4-channel audio)

  How to do that with ffmpeg ?

  • EDIT Adding ffprobe :

  Metadata :

  uid : ***

  generation_uid : ***

  company_name : CANON

  product_name : EOS C300 Mark II

  product_version : 1.00

  product_uid : ***

  modification_date : 2018-06-28T08:29:24.000000Z

  material_package_umid : ***

  timecode : 02:50:31:17

  Duration : 00:06:35.40, start : 0.000000, bitrate : 395842 kb/s

  Stream #0:0 : Video : h264 (High 4:2:2 Intra), yuv422p10le(tv, progressive), 3840x2160, SAR 1:1 DAR 16:9, 23.98 fps, 23.98 tbr, 23.98 tbn, 47.95 tbc

  Metadata :

   file_package_umid: ***

  Stream #0:1 : Audio : pcm_s24le, 48000 Hz, 1 channels, s32 (24 bit), 1152 kb/s

  Metadata :

   file_package_umid: ***

  Stream #0:2 : Audio : pcm_s24le, 48000 Hz, 1 channels, s32 (24 bit), 1152 kb/s

  Metadata :

   file_package_umid: ***

  Stream #0:3 : Audio : pcm_s24le, 48000 Hz, 1 channels, s32 (24 bit), 1152 kb/s

  Metadata :

   file_package_umid: ***

  Stream #0:4 : Audio : pcm_s24le, 48000 Hz, 1 channels, s32 (24 bit), 1152 kb/s

  Metadata :

   file_package_umid: ***

• How to save animations with tight layout, transparency and in high quality

  23 octobre 2023, par mapf

  I am trying to implement an option in my GUI to save an image sequence displayed using matplotlib. The code looks something like this :

  



  import matplotlib.pyplot as plt
from matplotlib.backends.backend_qt5agg import \
    FigureCanvasQTAgg as FigureCanvas
from matplotlib.animation import FuncAnimation
from PIL import Image


plt.rcParams['savefig.bbox'] = 'tight' 


class Printer:
    def __init__(self, data):
        self.fig, self.ax = plt.subplots()
        self.canvas = FigureCanvas(self.fig)

        # some irrelevant color adjustment here
        #self.ax.spines['bottom'].set_color('#f9f2d7')
        #self.ax.spines['top'].set_color('#f9f2d7')
        #self.ax.spines['right'].set_color('#f9f2d7')
        #self.ax.spines['left'].set_color('#f9f2d7')
        #self.ax.tick_params(axis='both', colors='#f9f2d7')
        #self.ax.yaxis.label.set_color('#f9f2d7')
        #self.ax.xaxis.label.set_color('#f9f2d7')
        #self.fig.subplots_adjust(left=0.1, right=0.975, bottom=0.09, top=0.98)
        self.fig.patch.set_alpha(0)
        self.fig.patch.set_visible(False)
        self.canvas.setStyleSheet("background-color:transparent;")
        self.fig.set_size_inches(10, 10, True)
        self.fig.tight_layout()

        self.data = data
        self.image_artist = self.ax.imshow(data[0])

    def animate(self, i):
        self.image_artist.set_data(self.data[i])
        self.canvas.draw()


def save_animation():
    data = [
        Image.open("test000.png"),
        Image.open("test001.png"),
    ]
    file = 'test.gif'
    printer = Printer(data)

    ani = FuncAnimation(
        printer.fig, printer.animate, interval=100, frames=len(data),
    )
    # writer = animation.writers['pillow'](bitrate=1000)
    ani.save(
        file, writer='pillow', savefig_kwargs={'transparent': True, 'bbox_inches': 'tight'}
    )


save_animation()


  



  Transparency :

  



  As you can see I have already tried several different approaches as suggested elsewhere (1, 2), but didn't manage to find a solution. All of the settings and arguments patch.set_alpha(0), patch.set_visible(False), canvas.setStyleSheet("background-color:transparent;"), savefig_kwargs={'transparent': True} seem to have no effect at all on the transparency. I found this post but I didn't get the code to work (for one I had to comment out this %matplotlib inline, but then I ended up getting some error during the MovieWriter.cleanup out = TextIOWrapper(BytesIO(out)).read() TypeError: a bytes-like object is required, not 'str'). Here, it was suggested that this is actually a bug, but the proposed workaroud doesn't work for me since I would have to rely on third-party software. There also exists this bug report which was supposedly solved, so maybe it is unrelated.

  



  Tight layout

  



  I actually couldn't really find much on this, but all the things I tried (plt.rcParams['savefig.bbox'] = 'tight', fig.tight_layout(), savefig_kwargs={'bbox_inches': 'tight'}) don't have any effect or are even actively discarded in the case of the bbox_inches argument. How does this work ?

  



  High quality

  



  Since I cannot use ImageMagick and can't get ffmpeg to work (more on this below), I rely on pillow to save my animation. But the only argument in terms of quality that I can pass on seems to be the bitrate, which doesn't have any effect. The files still have the same size and the animation still looks like mush. The only way that I found to increase the resolution was to use fig.set_size_inches(10, 10, True), but this still doesn't improve the overall quality of the animation. It still looks bad. I saw that you can pass on codec and extra_args so maybe that is something that might help, but I have no idea how to use these because I couldn't find a list with allowed arguments.

  



  ffmpeg

  



  I can't get ffmpeg to work. I installed the python package from here and can import it into a python session but I don't know how I can get matplotlib to use that. I also got ffmpeg from here (Windows 64-bit version) and set the plt.rcParams['animation.ffmpeg_path'] to where I saved the files (there was no intaller to run, not sure if I did it correctly). But this didn't help either. Also this is of course also third-party software, so if somebody else were to use my code/program it wouldn't work.

  


• Passing long url as string in python subprocess

  16 février 2015, par rogoro

  When I pass this long url as

   subprocess.Popen(["ffmpeg", "-i",
  
   "https://r6---sn-ufuxaxjvh-q4fe.googlevideo.com/videoplayback?pl=16&upn=1-Ch_dUO4YE&ipbits=0&requiressl=yes&sver=3&itag=22&ratebypass=yes&dur=86.053&source=youtube&sparams=dur%2Cid%2Cinitcwndbps%2Cip%2Cipbits%2Citag%2Cmime%2Cmm%2Cms%2Cmv%2Cpl%2Cratebypass%2Crequiressl%2Csource%2Cupn%2Cexpire&key=yt5&mime=video%2Fmp4&fexp=900805%2C907263%2C919150%2C927622%2C942901%2C943917%2C945089%2C947225%2C948124%2C948603%2C952302%2C952605%2C952612%2C952901%2C955301%2C957201%2C959701&expire=1424133614&id=o-ANRJvkk7EYBC4ug2L1u_aJ9BifNGN5wrOnqvWkhce-WT&mm=31&initcwndbps=5045000&signature=5DC013D85BE81A4EFFA9C7B9510865A5BB7E2121.3655C01D8075EAB4668D4AFB28C401896038470A&ip=137.144.99.102&ms=au&mv=m&mt=1424111820", "out.mp4"], stdout=subprocess.PIPE)

  It works.

  But It doesn’t when I pass it as variable.
  Example :

    link =
  
    "the_above_long_string"
  
  
  
   subprocess.Popen(["ffmpeg", "-i", link, "out.mp4"], stdout=subprocess.PIPE) // NOT WORKING

  Any idea how to make it work ?

  ---

  ERROR

  ffmpeg version N-69659-gc0367f7 Copyright (c) 2000-2015 the FFmpeg developers
  
    built with gcc 4.9.2 (GCC)
  
    configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-lzma --enable-decklink --enable-zlib
  
    libavutil      54. 18.100 / 54. 18.100
  
    libavcodec     56. 21.102 / 56. 21.102
  
    libavformat    56. 19.100 / 56. 19.100
  
    libavdevice    56.  4.100 / 56.  4.100
  
    libavfilter     5.  9.104 /  5.  9.104
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  1.100 /  1.  1.100
  
    libpostproc    53.  3.100 / 53.  3.100
  
  [tls @ 000000000033b9c0] The TLS connection was non-properly terminated.
  
  https://r6---sn-ufuxaxjvh-q4fe.googlevideo.com/videoplayback?sver=3&ratebypass=yes&signature=BD4B6B18A9753B2B99F8C439FD1A7D809E866740.D3822A9D82D67A0F92908863E08F887A101B58A7&initcwndbps=5112500&ipbits=0&source=youtube&dur=86.053&itag=22&pl=16&mime=video%2Fmp4&fexp=907263%2C927622%2C934954%2C9406738%2C9406963%2C943917%2C947225%2C948124%2C952302%2C952605%2C952612%2C952901%2C955301%2C957201%2C959701&mm=31&requiressl=yes&mt=1424116526&mv=m&ms=au&ip=137.144.99.102&key=yt5&upn=6MJQ3GrpFkA&expire=1424138291&sparams=dur%2Cid%2Cinitcwndbps%2Cip%2Cipbits%2Citag%2Cmime%2Cmm%2Cms%2Cmv%2Cpl%2Cratebypass%2Crequiressl%2Csource%2Cupn%2Cexpire&id=o-AGbNQ-s1alKbG-j05uoGOvT4MMeDv3qdgMqWZu-vGap9
  
  
  
  : Input/output error