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• avcodec/dstdec : Replace AC overread check by sample rate check

  1er juillet 2020, par Michael Niedermayer

  avcodec/dstdec : Replace AC overread check by sample rate check
  Real files do skip coding 0 bits at the end, thus this kind of check
  
  does not work reliable.
  Fixes : Ticket 8770
  
  Fixes : dst-256fs44-6ch-refdstencoder.dff
  The samplerate is specified in ISO/IEC 14496-3:2005(E) as one of 3 fixed
  
  values, this also can be used to limit the duration and avoid the timeout
  This reverts commit f6df99dba1ae64b05d08fba8160d13eb9795042f.
  

  • [DH] libavcodec/dstdec.c

• FFMPEG and Matplotlib for animations - strange outputs ?

  27 juin 2020, par user13132640

  I'm trying to create animations using FFMPEG and matplotlib. Using the below code, I am creating the FFMpeg writer, and then using a loop, writing a series of graphs to the animation. However, the outputs I'm getting are very strange ; sometimes, when I watch the .mp4 file, the first 5 seconds are blank, then the video "ends" (the playback time on my media player says that it's complete), and at that point, my animation shows up. Other times, some frames are missing or skipped. I've tried searching around, but frankly I haven't found anyone with similar issues.

  


  I just installed the latest version of FFMpeg today.

  


  FFMpegWriter = manimation.writers['ffmpeg']
metadata = dict(title='Animation test', artist='name')
writer = FFMpegWriter(fps=1, metadata=metadata) # 1 frames per second, each year is 1 second


  


  Then, the plotting part...(I've excluded the code where I setup the fig, ax etc.)

  


  with writer.saving(fig, "animation.mp4", dpi=200):
    year = "2005"
    for i in range(4):

        d1_plot = d1[d1['Year'].str.contains(year, na=False)]
        ax.scatter(d1_plot["Lat"], d1_plot["Long"], c='g', s=d1_plot["Size"], transform=ccrs.PlateCarree())
        ax.set_title(year)
        writer.grab_frame()
        year = str(int(year)+1)


  


• How to visualize matplotlib animation in Jupyter notebook

  23 avril 2020, par anonymous13

  I am trying to create a racing bar chart similar to the one in the link (https://towardsdatascience.com/bar-chart-race-in-python-with-matplotlib-8e687a5c8a41). 
However I am unable to see the animation in my Jupyter notebook

  



  code

  



  import pandas as pd
import matplotlib.pyplot as plt
import matplotlib.ticker as ticker
import matplotlib.animation as animation
from IPython.display import HTML

df = pd.read_csv('https://gist.githubusercontent.com/johnburnmurdoch/4199dbe55095c3e13de8d5b2e5e5307a/raw/fa018b25c24b7b5f47fd0568937ff6c04e384786/city_populations', 
                 usecols=['name', 'group', 'year', 'value'])

current_year = 2018
dff = (df[df['year'].eq(current_year)]
       .sort_values(by='value', ascending=True)
       .head(10))

colors = dict(zip(
    ['India', 'Europe', 'Asia', 'Latin America',
     'Middle East', 'North America', 'Africa'],
    ['#adb0ff', '#ffb3ff', '#90d595', '#e48381',
     '#aafbff', '#f7bb5f', '#eafb50']
))
group_lk = df.set_index('name')['group'].to_dict()


fig, ax = plt.subplots(figsize=(15, 8))
def draw_barchart(year):
    dff = df[df['year'].eq(year)].sort_values(by='value', ascending=True).tail(10)
    ax.clear()
    ax.barh(dff['name'], dff['value'], color=[colors[group_lk[x]] for x in dff['name']])
    dx = dff['value'].max() / 200
    for i, (value, name) in enumerate(zip(dff['value'], dff['name'])):
        ax.text(value-dx, i,     name,           size=14, weight=600, ha='right', va='bottom')
        ax.text(value-dx, i-.25, group_lk[name], size=10, color='#444444', ha='right', va='baseline')
        ax.text(value+dx, i,     f'{value:,.0f}',  size=14, ha='left',  va='center')
    # ... polished styles
    ax.text(1, 0.4, year, transform=ax.transAxes, color='#777777', size=46, ha='right', weight=800)
    ax.text(0, 1.06, 'Population (thousands)', transform=ax.transAxes, size=12, color='#777777')
    ax.xaxis.set_major_formatter(ticker.StrMethodFormatter('{x:,.0f}'))
    ax.xaxis.set_ticks_position('top')
    ax.tick_params(axis='x', colors='#777777', labelsize=12)
    ax.set_yticks([])
    ax.margins(0, 0.01)
    ax.grid(which='major', axis='x', linestyle='-')
    ax.set_axisbelow(True)
    ax.text(0, 1.12, 'The most populous cities in the world from 1500 to 2018',
            transform=ax.transAxes, size=24, weight=600, ha='left')
    ax.text(1, 0, 'by @pratapvardhan; credit @jburnmurdoch', transform=ax.transAxes, ha='right',
            color='#777777', bbox=dict(facecolor='white', alpha=0.8, edgecolor='white'))
    plt.box(False)

draw_barchart(2018)

import matplotlib.animation as animation
from IPython.display import HTML
fig, ax = plt.subplots(figsize=(15, 8))
animator = animation.FuncAnimation(fig, draw_barchart, frames=range(1968, 2019))
HTML(animator.to_jshtml()) 



  



  Below is what I tried using and the errors

  



  HTML(animator.to_jshtml())  <-- Static output with buttons unable to visualize animation
plt.rcParams["animation.html"] = "jshtml"  <- no error and output
HTML(animator.to_html5_video())  <---Requested MovieWriter (ffmpeg) not available 



  



  Note I have FFmpeg installed in my system.
Can you help me with the issue