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La sauvegarde automatique de canaux SPIP
1er avril 2010, parDans le cadre de la mise en place d’une plateforme ouverte, il est important pour les hébergeurs de pouvoir disposer de sauvegardes assez régulières pour parer à tout problème éventuel.
Pour réaliser cette tâche on se base sur deux plugins SPIP : Saveauto qui permet une sauvegarde régulière de la base de donnée sous la forme d’un dump mysql (utilisable dans phpmyadmin) mes_fichiers_2 qui permet de réaliser une archive au format zip des données importantes du site (les documents, les éléments (...) -
Script d’installation automatique de MediaSPIP
25 avril 2011, parAfin de palier aux difficultés d’installation dues principalement aux dépendances logicielles coté serveur, un script d’installation "tout en un" en bash a été créé afin de faciliter cette étape sur un serveur doté d’une distribution Linux compatible.
Vous devez bénéficier d’un accès SSH à votre serveur et d’un compte "root" afin de l’utiliser, ce qui permettra d’installer les dépendances. Contactez votre hébergeur si vous ne disposez pas de cela.
La documentation de l’utilisation du script d’installation (...) -
Automated installation script of MediaSPIP
25 avril 2011, parTo overcome the difficulties mainly due to the installation of server side software dependencies, an "all-in-one" installation script written in bash was created to facilitate this step on a server with a compatible Linux distribution.
You must have access to your server via SSH and a root account to use it, which will install the dependencies. Contact your provider if you do not have that.
The documentation of the use of this installation script is available here.
The code of this (...)
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FFmpeg stuck on last frame
9 septembre 2022, par Diana Savii'm having issues with my code


I'm using a input mxf with 1 stereo channel to a mxf output with 16 mono channels for tv broadcast equipment, which have a specific pattern like this :


[A1][A2][A3][A4][MUTE5][MUTE6][MUTE7][MUTE8][A9][A10][A11][A12][MUTE13][MUTE14][MUTE15][MUTE16]


so i made this :


ffmpeg -i shorttest.mxf -f lavfi -i anullsrc=channel_layout=mono -ac:0 1 -map_metadata -1 -map 0:v -map 0:a -map 0:a -map 1:a -map 1:a -map 1:a -map 1:a -map 0:a -map 0:a -map 1:a -map 1:a -map 1:a -map 1:a -vcodec mpeg2video -ar 48000 OUTPUT8CH.mxf

the problem is when i do that it stucks on the very last frame, consuming a lot of RAM and eventually crashing


`frame= 208 fps= 26 q=31.0 size= 13568kB time=00:26:50.28 bitrate= 69.0kbits/s speed=200x


so i'm trying to figure out what's wrong, can someone help me ?


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FFmpeg MXF converting stuck on last frame
9 septembre 2022, par Diana Savii'm having issues with my code


I'm converting a input mxf with 1 stereo channel to a mxf output with 16 mono channels for tv broadcast equipment, which have a specific pattern like this :


[A1][A2][A3][A4][MUTE5][MUTE6][MUTE7][MUTE8][A9][A10][A11][A12][MUTE13][MUTE14][MUTE15][MUTE16]


so i made this :


ffmpeg -i shorttest.mxf -f lavfi -i anullsrc=channel_layout=mono -ac:0 1 -map_metadata -1 -map 0:v -map 0:a -map 0:a -map 1:a -map 1:a -map 1:a -map 1:a -map 0:a -map 0:a -map 1:a -map 1:a -map 1:a -map 1:a -vcodec mpeg2video -ar 48000 OUTPUT8CH.mxf

the problem is when i do that it stucks on the very last frame, consuming a lot of RAM and eventually crashing


`frame= 208 fps= 26 q=31.0 size= 13568kB time=00:26:50.28 bitrate= 69.0kbits/s speed=200x


so i'm trying to figure out what's wrong, can someone help me ?


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ffmpeg : Downmixing 5.1 to stereo with phase invert
1er novembre 2022, par anti-heroI'd like to use ffmpeg and Dolby Logic Pro II formula to downmix a 5.1 song to stereo :




Lt = L + (–3 dB × C) – (–1.2 dB × Ls) – (–6.2 dB × Rs)


Rt = R + (–3 dB × C) + (–6.2 dB × Ls) + (–1.2 dB × Rs)




I came up with this long and probably redundant bash script :


# L channel
ffmpeg -i "$filename" -map_channel 0.1.0 -c:a pcm_f32le L.wav
ffmpeg -i "$filename" -map_channel 0.1.2 -filter:a "volume=-3dB" -c:a pcm_f32le C.wav
ffmpeg -i "$filename" -map_channel 0.1.4 -af "volume=-1.2dB" -c:a pcm_f32le Ls.wav
ffmpeg -i "$filename" -map_channel 0.1.5 -af "volume=-6.2dB" -c:a pcm_f32le Rs.wav
ffmpeg -i Ls.wav -af "aeval=-val(0)" -c:a pcm_f32le Lsi.wav
ffmpeg -i Rs.wav -af "aeval=-val(0)" -c:a pcm_f32le Rsi.wav
ffmpeg -i L.wav -i C.wav -i Lsi.wav -i Rsi.wav -filter_complex "amix=inputs=4" -c:a pcm_f32le L_final.wav
rm L.wav Ls.wav Rs.wav Lsi.wav Rsi.wav

# R channel
ffmpeg -i "$filename" -map_channel 0.1.1 -c:a pcm_f32le R.wav
ffmpeg -i "$filename" -map_channel 0.1.4 -filter:a "volume=-6.2dB" -c:a pcm_f32le Ls.wav
ffmpeg -i "$filename" -map_channel 0.1.5 -filter:a "volume=-1.2dB" -c:a pcm_f32le Rs.wav
ffmpeg -i R.wav -i C.wav -i Ls.wav -i Rs.wav -filter_complex "amix=inputs=4" -c:a pcm_f32le R_final.wav
rm R.wav C.wav Ls.wav Rs.wav

# Mix
ffmpeg -i L_final.wav -i R_final.wav -filter_complex "[0:0][1:0] amerge=inputs=2" -c:a pcm_f32le "${filename%.*}_dm.wav"
rm L_final.wav R_final.wav


Would this work ? And is there a simpler way to do this ?


update : I also wrote Python code for the 90 degree phase shift version.


import scipy, os, numpy as np

os.system(f'ffmpeg -i "{filename}" -c:a pcm_f32le temp.wav')
sample_rate, waves = scipy.io.wavfile.read("temp.wav")
os.remove("temp.wav")

L, R, C, LFE, LS, RS = waves.T

LS_shifted = -np.imag(scipy.signal.hilbert(LS))
RS_shifted = np.imag(scipy.signal.hilbert(RS))
L_out = L + 0.708 * C - 0.871 * LS_shifted - 0.49 * RS_shifted
R_out = R + 0.708 * C + 0.49 * LS_shifted + 0.871 * RS_shifted

scipy.io.wavfile.write("out.wav", sample_rate, np.vstack((L_out, R_out)).T)


Hope someone finds this useful ! (and that someone verifies it's correct)


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