Traceback (most recent call last):

 "C:\dev\youtube-dl\master\youtube_dl\YoutubeDL.py", line 1786, in post_process
files_to_delete, info = pp.run(info)

 "C:\dev\youtube-dl\master\youtube_dl\postprocessor\ffmpeg.py", line 446, in run
self.run_ffmpeg_multiple_files(info['__files_to_merge'], temp_filename, args)

 "C:\dev\youtube-dl\master\youtube_dl\postprocessor\ffmpeg.py", line 168, in run_ffmpeg_multiple_files
raise FFmpegPostProcessorError(msg)youtube_dl.postprocessor.ffmpeg.FFmpegPostProcessorError: Conversion failed!
Traceback (most recent call last):

 "examples/lmfit_and_emcee.py", line 99, in <module>
lnfunc, guess = create_all(mini)

 "examples/lmfit_and_emcee.py", line 66, in create_all
guess = starting_guess(mini, not sigma_given)

 "examples/lmfit_and_emcee.py", line 52, in starting_guess
vals.append(mini.residual.std())AttributeError: 'NoneType' object has no attribute 'std'