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• how do I save the videos in an specific bitrate using ffmpeg ?

  15 mai 2022, par david

  I am trying to save some videos in specific bitrate (8000k) and for this, I used the following code :

  


  ffmpeg  -i  input_1080p60  -c:v  libx264 -pix_fmt yuv420p  -b:v 8000K -bufsize 8000K -minrate 8000K -maxrate 8000K -x264opts keyint=120:min-keyint=120 -preset veryfast -profile:v high out_1080p.264


  


  but after saving the videos, I find out each video has a different bitrate except 8000k ( for example 5000k, 6000k, 7500k,...). but I define the minrate 8000k. do you know what is the problem and how can I force the above code to have the specific bitrate ? Thank you.

  


• Unknown input format : 'rawvideo' when trying to save animation

  8 juin 2022, par John Klint

  So, I get a strange error trying to save animations created with matplotlib.FuncAnimation using FFMpegWriter.

  


  /home/j/PycharmProjects/venvtest/venv/bin/python /home/j/PycharmProjects/venvtest/main.py&#xA;MovieWriter stderr:&#xA;Unknown input format: &#x27;rawvideo&#x27;&#xA;&#xA;Traceback (most recent call last):&#xA;  File "/home/j/PycharmProjects/venvtest/venv/lib/python3.9/site-packages/matplotlib/animation.py", line 234, in saving&#xA;    yield self&#xA;  File "/home/j/PycharmProjects/venvtest/venv/lib/python3.9/site-packages/matplotlib/animation.py", line 1093, in save&#xA;    writer.grab_frame(**savefig_kwargs)&#xA;  File "/home/j/PycharmProjects/venvtest/venv/lib/python3.9/site-packages/matplotlib/animation.py", line 351, in grab_frame&#xA;    self.fig.savefig(self._proc.stdin, format=self.frame_format,&#xA;  File "/home/j/PycharmProjects/venvtest/venv/lib/python3.9/site-packages/matplotlib/figure.py", line 3046, in savefig&#xA;    self.canvas.print_figure(fname, **kwargs)&#xA;  File "/home/j/PycharmProjects/venvtest/venv/lib/python3.9/site-packages/matplotlib/backend_bases.py", line 2319, in print_figure&#xA;    result = print_method(&#xA;  File "/home/j/PycharmProjects/venvtest/venv/lib/python3.9/site-packages/matplotlib/backend_bases.py", line 1648, in wrapper&#xA;    return func(*args, **kwargs)&#xA;  File "/home/j/PycharmProjects/venvtest/venv/lib/python3.9/site-packages/matplotlib/_api/deprecation.py", line 415, in wrapper&#xA;    return func(*inner_args, **inner_kwargs)&#xA;  File "/home/j/PycharmProjects/venvtest/venv/lib/python3.9/site-packages/matplotlib/backends/backend_agg.py", line 486, in print_raw&#xA;    fh.write(renderer.buffer_rgba())&#xA;BrokenPipeError: [Errno 32] Broken pipe&#xA;&#xA;During handling of the above exception, another exception occurred:&#xA;&#xA;Traceback (most recent call last):&#xA;  File "/home/j/PycharmProjects/venvtest/main.py", line 24, in <module>&#xA;    anim.save(&#x27;basic_animation.mp4&#x27;, writer=FFwriter)&#xA;  File "/home/j/PycharmProjects/venvtest/venv/lib/python3.9/site-packages/matplotlib/animation.py", line 1093, in save&#xA;    writer.grab_frame(**savefig_kwargs)&#xA;  File "/usr/lib/python3.9/contextlib.py", line 137, in __exit__&#xA;    self.gen.throw(typ, value, traceback)&#xA;  File "/home/j/PycharmProjects/venvtest/venv/lib/python3.9/site-packages/matplotlib/animation.py", line 236, in saving&#xA;    self.finish()&#xA;  File "/home/j/PycharmProjects/venvtest/venv/lib/python3.9/site-packages/matplotlib/animation.py", line 342, in finish&#xA;    self._cleanup()  # Inline _cleanup() once cleanup() is removed.&#xA;  File "/home/j/PycharmProjects/venvtest/venv/lib/python3.9/site-packages/matplotlib/animation.py", line 373, in _cleanup&#xA;    raise subprocess.CalledProcessError(&#xA;subprocess.CalledProcessError: Command &#x27;[&#x27;/usr/bin/ffmpeg&#x27;, &#x27;-f&#x27;, &#x27;rawvideo&#x27;, &#x27;-vcodec&#x27;, &#x27;rawvideo&#x27;, &#x27;-s&#x27;, &#x27;640x480&#x27;, &#x27;-pix_fmt&#x27;, &#x27;rgba&#x27;, &#x27;-r&#x27;, &#x27;5&#x27;, &#x27;-loglevel&#x27;, &#x27;error&#x27;, &#x27;-i&#x27;, &#x27;pipe:&#x27;, &#x27;-vcodec&#x27;, &#x27;h264&#x27;, &#x27;-pix_fmt&#x27;, &#x27;yuv420p&#x27;, &#x27;-y&#x27;, &#x27;basic_animation.mp4&#x27;]&#x27; returned non-zero exit status 1.&#xA;&#xA;Process finished with exit code 1&#xA;</module>

  


  I am confident it has nothing to do with the animation data, the error occurs even when I create a simple test animation :

  


  import numpy as np
from matplotlib import pyplot as plt
from matplotlib import animation
# plt.rcParams['animation.ffmpeg_path'] = '/usr/bin/ffmpeg'

fig = plt.figure()
ax = plt.axes(xlim=(0, 2), ylim=(-2, 2))
line, = ax.plot([], [], lw=2)


def init():
    line.set_data([], [])
    return line,


def animate(i):
    x = np.linspace(0, 2, 1000)
    y = np.sin(2 * np.pi * (x - 0.01 * i))
    line.set_data(x, y)
    return line,


anim = animation.FuncAnimation(fig, animate, init_func=init,
                           frames=200, interval=20, blit=True)

FFwriter = animation.FFMpegWriter()
anim.save('basic_animation.mp4', writer=FFwriter)


  


  I am currently using PyCharm in LinuxMint and I have a fairly new version of FFMpeg (4.2.4) installed. Given that FFMpeg complains about 'rawvideo' which as far as I understand it is just a bunch of images in series, it seems unlikely this has anything to do with codecs. If I run ffmpeg -formats, sure enough rawvideo is in the list.

  


  I have tried manually setting plt.rcParams, like in the commented line in the code above, with no success. I have also tried setting up both anaconda and venv environments, but I get the same error.
Annoyingly, I did not have this problem a few months ago when I was using Ubuntu. I have also verified that it works on my friends Ubuntu desktop, using the same simple venv as I set up for myself.

  


  Any ideas ?

  


  EDIT : I use the fish shell, if that is relevant...

  


  Well this is peculiar. If I start a terminal from within PyCharm and check supported formats, I get the following :

  


  (venv) ffmpeg -formats
ffmpeg version 4.3.4 Copyright (c) 2000-2021 the FFmpeg developers
  built with gcc 11.3.0 (GCC)
  configuration: --prefix=/usr --libdir=/usr/lib/x86_64-linux-gnu --disable-debug --disable-doc --disable-static --enable-optimizations --enable-shared --disable-everything --enable-ffplay --enable-ffprobe --enable-gnutls --enable-libaom --enable-libdav1d --enable-libfdk-aac --enable-libmp3lame --enable-libfontconfig --enable-libfreetype --enable-libopus --enable-libpulse --enable-libspeex --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libwebp --enable-openal --enable-opengl --enable-sdl2 --enable-vulkan --enable-zlib --enable-libv4l2 --enable-libxcb --enable-vdpau --enable-vaapi --enable-encoder='ac3,alac,flac,libfdk_aac,g723_1,mp2,libmp3lame,libopus,libspeex,pcm_alaw,pcm_mulaw,pcm_f32le,pcm_s16be,pcm_s24be,pcm_s16le,pcm_s24le,pcm_s32le,pcm_u8,tta,libvorbis,wavpack,' --enable-encoder='ass,ffv1,libaom_av1,libvpx_vp8,libvpx_vp9,mjpeg_vaapi,rawvideo,theora,vp8_vaapi,libopenh264' --enable-decoder='adpcm_g722,alac,flac,g723_1,g729,libfdk_aac,libopus,libspeex,mp2,mp3,m4a,pcm_alaw,pcm_mulaw,pcm_f16le,pcm_f24le,pcm_f32be,pcm_f32le,pcm_f64be,pcm_f64le,pcm_s16be,pcm_s16be_planar,pcm_s24be,pcm_s16le,pcm_s16le_planar,pcm_s24le,pcm_s24le_planar,pcm_s32le,pcm_s32le_planar,pcm_s64be,pcm_s64le,pcm_s8,pcm_s8_planar,pcm_u8,pcm_u24be,pcm_u24le,pcm_u32be,pcm_u32le,tta,vorbis,wavpack,' --enable-decoder='ass,ffv1,mjpeg,mjpegb,libaom_av1,libdav1d,libvpx_vp8,libvpx_vp9,rawvideo,theora,vp8,vp9,libopenh264' --enable-encoder='bmp,gif,jpegls,png,tiff,webp,' --enable-decoder='bmp,gif,jpegls,png,tiff,webp,' --enable-hwaccel='vp8_vaapi,mjpeg_vaapi,' --enable-parser='aac,ac3,flac,mjpeg,mpegaudio,mpeg4video,opus,vp3,vp8,vp9,vorbis,' --enable-muxer='ac3,ass,flac,g722,gif,matroska,mp3,mpegvideo,rtp,ogg,opus,pcm_s16be,pcm_s16le,wav,webm,' --enable-demuxer='aac,ac3,ass,flac,g722,gif,image_jpeg_pipe,image_png_pipe,image_webp_pipe,matroska,mjpeg,mov,mp3,mpegvideo,ogg,pcm_mulaw,pcm_alaw,pcm_s16be,pcm_s16le,rtp,wav,' --enable-filter='crop,scale,overlay,amix,amerge,aresample,format,aformat,fps,transpose,pad,' --enable-protocol='crypto,file,pipe,rtp,srtp,rtsp,tcp,udp,unix,' --arch=x86_64 --enable-libopenh264
  libavutil      56. 51.100 / 56. 51.100
  libavcodec     58. 91.100 / 58. 91.100
  libavformat    58. 45.100 / 58. 45.100
  libavdevice    58. 10.100 / 58. 10.100
  libavfilter     7. 85.100 /  7. 85.100
  libswscale      5.  7.100 /  5.  7.100
  libswresample   3.  7.100 /  3.  7.100
File formats:
 D. = Demuxing supported
 .E = Muxing supported
 --
 D  aac             raw ADTS AAC (Advanced Audio Coding)
 DE ac3             raw AC-3
 D  alaw            PCM A-law
 D  asf             ASF (Advanced / Active Streaming Format)
 DE ass             SSA (SubStation Alpha) subtitle
 DE flac            raw FLAC
 DE g722            raw G.722
 DE gif             CompuServe Graphics Interchange Format (GIF)
 D  jpeg_pipe       piped jpeg sequence
  E matroska        Matroska
 D  matroska,webm   Matroska / WebM
 D  mjpeg           raw MJPEG video
 D  mov,mp4,m4a,3gp,3g2,mj2 QuickTime / MOV
 DE mp3             MP3 (MPEG audio layer 3)
 D  mpegts          MPEG-TS (MPEG-2 Transport Stream)
 D  mpegvideo       raw MPEG video
 D  mulaw           PCM mu-law
 DE ogg             Ogg
  E opus            Ogg Opus
 D  png_pipe        piped png sequence
 D  rm              RealMedia
 DE rtp             RTP output
 DE s16be           PCM signed 16-bit big-endian
 DE s16le           PCM signed 16-bit little-endian
 D  sdp             SDP
 DE wav             WAV / WAVE (Waveform Audio)
  E webm            WebM
 D  webp_pipe       piped webp sequence



  


  As is evident, there is no support for 'rawvideo' in the list above ! Very strange indeed, I do not know which ffmpeg this list belongs to, perhaps it is a version integrated into matplotlib's animation class ?

  


  Anyway, if I uncomment the line setting the ffmpeg_path I am back at the old error. I did get it to work however, by changing the path from '/usr/bin/ffmpeg' to '/home/j/.conda/envs/venvtest/bin/ffmpeg'. Then I get the file to run, create the animation and save it. This works for my real files as well, which do not even run that particular conda-environment. They do not recognize or find the ffmpeg I have in /usr/bin though. I have no clue why but at least I have a workaround now.

  


  Final edit :
It is solved. It was flatpak's fault. Lesson is, don't use flatpak (or snap for that matter) to install Pycharm.

  


• Save video clip from longer video between two timestamps in Python cv2

  14 juin 2022, par Elizabeth Orrico

  I have an hour-long video that I would like to save a clip between two timestamps— say, 11:20-11:35. Is the best way to do this frame-by-frame, or is there a better way ?