Recherche avancée

Médias (91)

Autres articles (99)

  • MediaSPIP 0.1 Beta version

    25 avril 2011, par

    MediaSPIP 0.1 beta is the first version of MediaSPIP proclaimed as "usable".
    The zip file provided here only contains the sources of MediaSPIP in its standalone version.
    To get a working installation, you must manually install all-software dependencies on the server.
    If you want to use this archive for an installation in "farm mode", you will also need to proceed to other manual (...)

  • ANNEXE : Les plugins utilisés spécifiquement pour la ferme

    5 mars 2010, par

    Le site central/maître de la ferme a besoin d’utiliser plusieurs plugins supplémentaires vis à vis des canaux pour son bon fonctionnement. le plugin Gestion de la mutualisation ; le plugin inscription3 pour gérer les inscriptions et les demandes de création d’instance de mutualisation dès l’inscription des utilisateurs ; le plugin verifier qui fournit une API de vérification des champs (utilisé par inscription3) ; le plugin champs extras v2 nécessité par inscription3 (...)

  • Activation de l’inscription des visiteurs

    12 avril 2011, par

    Il est également possible d’activer l’inscription des visiteurs ce qui permettra à tout un chacun d’ouvrir soit même un compte sur le canal en question dans le cadre de projets ouverts par exemple.
    Pour ce faire, il suffit d’aller dans l’espace de configuration du site en choisissant le sous menus "Gestion des utilisateurs". Le premier formulaire visible correspond à cette fonctionnalité.
    Par défaut, MediaSPIP a créé lors de son initialisation un élément de menu dans le menu du haut de la page menant (...)

Sur d’autres sites (8848)

  • lavu/tx : add length decomposition function

    18 novembre 2022, par Lynne
    lavu/tx : add length decomposition function

    Rather than using a list of lengths supported, this goes a step beyond
    
and uses all registered codelets to come up with a good decomposition.
    • [DH] libavutil/tx.c
    • [DH] libavutil/tx_priv.h

  • lavu/tx : implement aarch64 NEON SIMD FFT

    3 février 2022, par Lynne
    lavu/tx : implement aarch64 NEON SIMD FFT

    The fastest fast Fourier transform in not just the west, but the world,
    
now for the most popular toy ISA.
    

    On a high level, it follows the design of the AVX2 version closely,
    
with the exception that the input is slightly less permuted as we don't have
    
to do lane switching with the input on double 4pt and 8pt.
    

    On a low level, the lack of subadd/addsub instructions REALLY penalizes
    
any attempt at writing an FFT. That single register matters a lot,
    
and reloading it simply takes unacceptably long.
    
In x86 land, vendors would've noticed developers need this.
    
In ARM land, you get a badly designed complex multiplication instruction
    
we cannot use, that's not present on 95% of devices. Because only
    
compilers matter, right ?
    

    Future optimization options are very few, perhaps better register
    
management to use more ld1/st1s.
    

    All timings below are in cycles :
    
A53 :
    
Length | C           | New (lavu)  | Old (lavc)  | FFTW
    

    

     |-------------|-------------|-------------|-----
    
4      |         842 | 420         | 1210        | 1460
    
8      |        1538 | 1020        | 1850        | 2520
    
16     |        3717 | 1900        | 3700        | 3990
    
32     |        9156 | 4070        | 8289        | 8860
    
64     |       21160 | 9931        | 18600       | 19625
    
128    |       49180 | 23278       | 41922       | 41922
    
256    |      112073 | 53876       | 93202       | 101092
    
512    |      252864 | 122884      | 205897      | 207868
    
1024   |      560512 | 278322      | 458071      | 453053
    
2048   |     1295402 | 775835      | 1038205     | 1020265
    
4096   |     3281263 | 2021221     | 2409718     | 2577554
    
8192   |     8577845 | 4780526     | 5673041     | 6802722
    

    Apple M1
    
New  - Total for len 512 reps 2097152 = 1.459141 s
    
Old  - Total for len 512 reps 2097152 = 2.251344 s
    
FFTW - Total for len 512 reps 2097152 = 1.868429 s
    

    New  - Total for len 1024 reps 4194304 = 6.490080 s
    
Old  - Total for len 1024 reps 4194304 = 9.604949 s
    
FFTW - Total for len 1024 reps 4194304 = 7.889281 s
    

    New  - Total for len 16384 reps 262144 = 10.374001 s
    
Old  - Total for len 16384 reps 262144 = 15.266713 s
    
FFTW - Total for len 16384 reps 262144 = 12.341745 s
    

    New  - Total for len 65536 reps 8192 = 1.769812 s
    
Old  - Total for len 65536 reps 8192 = 4.209413 s
    
FFTW - Total for len 65536 reps 8192 = 3.012365 s
    

    New  - Total for len 131072 reps 4096 = 1.942836 s
    
Old  - Segfaults
    
FFTW - Total for len 131072 reps 4096 = 3.713713 s
    

    Thanks to wbs for some simplifications, assembler fixes and a review
    
and to jannau for giving it a look.
    • [DH] libavutil/aarch64/Makefile
    • [DH] libavutil/aarch64/tx_float_init.c
    • [DH] libavutil/aarch64/tx_float_neon.S
    • [DH] libavutil/tx.c
    • [DH] libavutil/tx_priv.h

  • Why is the average value on the console different from the average value calculated through the log when ffmpeg calculates PSNR ?

    29 juillet 2022, par will

    I’m using ffmpeg to calculate PSNR.

    


    The average PSNR output on the console is 43.786363.

    


    ffmpeg -i distorted.mp4 -i reference.mp4 -lavfi psnr=stats_file=psnr.log -f null -

frame=   60 fps=0.0 q=-0.0 Lsize=N/A time=00:00:02.00 bitrate=N/A speed=74.7x
video:31kB audio:348kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
[Parsed_psnr_0 @ 0x7ff8a1e12600] PSNR y:43.002640 u:45.749688 v:46.207664 average:43.786363 min:42.635801 max:46.166560


    


    But the average value of per frame psnr_avg in psnr log is 43.90816666666668.

    


    psnr_list = []
with open('psnr.log', 'r') as f:
    for line in f:
        psnr = float(line.split('psnr_avg:')[-1].split(' ')[0])
        psnr_list.append(psnr)
print(sum(psnr_list) / len(psnr_list))


    


    n:1 mse_avg:1.57 mse_y:1.86 mse_u:1.05 mse_v:0.93 psnr_avg:46.17 psnr_y:45.43 psnr_u:47.94 psnr_v:48.45 
n:2 mse_avg:1.63 mse_y:1.95 mse_u:1.06 mse_v:0.95 psnr_avg:46.00 psnr_y:45.23 psnr_u:47.86 psnr_v:48.37 
n:3 mse_avg:1.64 mse_y:1.96 mse_u:1.07 mse_v:0.95 psnr_avg:45.98 psnr_y:45.22 psnr_u:47.86 psnr_v:48.37 
n:4 mse_avg:1.64 mse_y:1.96 mse_u:1.06 mse_v:0.93 psnr_avg:45.99 psnr_y:45.22 psnr_u:47.86 psnr_v:48.44 
n:5 mse_avg:1.64 mse_y:1.96 mse_u:1.06 mse_v:0.93 psnr_avg:45.99 psnr_y:45.21 psnr_u:47.86 psnr_v:48.46 
n:6 mse_avg:1.69 mse_y:2.03 mse_u:1.06 mse_v:0.97 psnr_avg:45.85 psnr_y:45.06 psnr_u:47.86 psnr_v:48.25 
n:7 mse_avg:1.73 mse_y:2.06 mse_u:1.11 mse_v:1.03 psnr_avg:45.75 psnr_y:44.99 psnr_u:47.69 psnr_v:48.01 
n:8 mse_avg:1.90 mse_y:2.22 mse_u:1.24 mse_v:1.26 psnr_avg:45.35 psnr_y:44.67 psnr_u:47.19 psnr_v:47.12 
n:9 mse_avg:1.89 mse_y:2.22 mse_u:1.21 mse_v:1.25 psnr_avg:45.38 psnr_y:44.68 psnr_u:47.30 psnr_v:47.17 
n:10 mse_avg:1.90 mse_y:2.23 mse_u:1.25 mse_v:1.21 psnr_avg:45.35 psnr_y:44.64 psnr_u:47.16 psnr_v:47.31 
n:11 mse_avg:1.91 mse_y:2.25 mse_u:1.26 mse_v:1.22 psnr_avg:45.31 psnr_y:44.61 psnr_u:47.14 psnr_v:47.28 
n:12 mse_avg:1.92 mse_y:2.27 mse_u:1.32 mse_v:1.14 psnr_avg:45.29 psnr_y:44.58 psnr_u:46.92 psnr_v:47.58 
n:13 mse_avg:2.39 mse_y:2.82 mse_u:1.72 mse_v:1.34 psnr_avg:44.35 psnr_y:43.64 psnr_u:45.79 psnr_v:46.85 
n:14 mse_avg:2.38 mse_y:2.84 mse_u:1.56 mse_v:1.35 psnr_avg:44.37 psnr_y:43.60 psnr_u:46.21 psnr_v:46.84 
n:15 mse_avg:2.37 mse_y:2.83 mse_u:1.54 mse_v:1.34 psnr_avg:44.39 psnr_y:43.62 psnr_u:46.24 psnr_v:46.87 
n:16 mse_avg:2.39 mse_y:2.85 mse_u:1.59 mse_v:1.37 psnr_avg:44.34 psnr_y:43.58 psnr_u:46.12 psnr_v:46.76 
n:17 mse_avg:2.39 mse_y:2.85 mse_u:1.58 mse_v:1.36 psnr_avg:44.35 psnr_y:43.58 psnr_u:46.15 psnr_v:46.80 
n:18 mse_avg:2.36 mse_y:2.79 mse_u:1.60 mse_v:1.36 psnr_avg:44.41 psnr_y:43.67 psnr_u:46.10 psnr_v:46.78 
n:19 mse_avg:2.33 mse_y:2.77 mse_u:1.58 mse_v:1.35 psnr_avg:44.45 psnr_y:43.71 psnr_u:46.14 psnr_v:46.83 
n:20 mse_avg:2.39 mse_y:2.86 mse_u:1.55 mse_v:1.36 psnr_avg:44.34 psnr_y:43.57 psnr_u:46.22 psnr_v:46.78 
n:21 mse_avg:2.46 mse_y:2.94 mse_u:1.59 mse_v:1.38 psnr_avg:44.23 psnr_y:43.45 psnr_u:46.12 psnr_v:46.73 
n:22 mse_avg:2.49 mse_y:2.94 mse_u:1.68 mse_v:1.51 psnr_avg:44.17 psnr_y:43.45 psnr_u:45.88 psnr_v:46.34 
n:23 mse_avg:2.48 mse_y:2.92 mse_u:1.69 mse_v:1.52 psnr_avg:44.18 psnr_y:43.47 psnr_u:45.85 psnr_v:46.32 
n:24 mse_avg:2.48 mse_y:2.93 mse_u:1.70 mse_v:1.45 psnr_avg:44.19 psnr_y:43.46 psnr_u:45.83 psnr_v:46.52 
n:25 mse_avg:2.51 mse_y:2.93 mse_u:1.78 mse_v:1.59 psnr_avg:44.13 psnr_y:43.47 psnr_u:45.64 psnr_v:46.13 
n:26 mse_avg:2.79 mse_y:3.29 mse_u:1.90 mse_v:1.68 psnr_avg:43.68 psnr_y:42.97 psnr_u:45.34 psnr_v:45.89 
n:27 mse_avg:2.75 mse_y:3.25 mse_u:1.87 mse_v:1.64 psnr_avg:43.74 psnr_y:43.02 psnr_u:45.41 psnr_v:45.97 
n:28 mse_avg:2.72 mse_y:3.24 mse_u:1.72 mse_v:1.64 psnr_avg:43.79 psnr_y:43.03 psnr_u:45.79 psnr_v:45.98 
n:29 mse_avg:2.77 mse_y:3.28 mse_u:1.77 mse_v:1.75 psnr_avg:43.70 psnr_y:42.97 psnr_u:45.65 psnr_v:45.71 
n:30 mse_avg:2.79 mse_y:3.34 mse_u:1.71 mse_v:1.64 psnr_avg:43.68 psnr_y:42.89 psnr_u:45.81 psnr_v:46.00 
n:31 mse_avg:2.75 mse_y:3.33 mse_u:1.64 mse_v:1.57 psnr_avg:43.73 psnr_y:42.91 psnr_u:45.99 psnr_v:46.18 
n:32 mse_avg:2.82 mse_y:3.42 mse_u:1.61 mse_v:1.66 psnr_avg:43.63 psnr_y:42.80 psnr_u:46.07 psnr_v:45.94 
n:33 mse_avg:2.87 mse_y:3.46 mse_u:1.66 mse_v:1.68 psnr_avg:43.56 psnr_y:42.74 psnr_u:45.92 psnr_v:45.86 
n:34 mse_avg:2.90 mse_y:3.51 mse_u:1.70 mse_v:1.64 psnr_avg:43.51 psnr_y:42.67 psnr_u:45.82 psnr_v:45.99 
n:35 mse_avg:2.95 mse_y:3.56 mse_u:1.76 mse_v:1.70 psnr_avg:43.44 psnr_y:42.62 psnr_u:45.68 psnr_v:45.83 
n:36 mse_avg:2.84 mse_y:3.44 mse_u:1.66 mse_v:1.66 psnr_avg:43.59 psnr_y:42.77 psnr_u:45.94 psnr_v:45.92 
n:37 mse_avg:3.25 mse_y:3.90 mse_u:1.97 mse_v:1.89 psnr_avg:43.02 psnr_y:42.22 psnr_u:45.18 psnr_v:45.37 
n:38 mse_avg:3.25 mse_y:3.89 mse_u:2.05 mse_v:1.87 psnr_avg:43.02 psnr_y:42.23 psnr_u:45.02 psnr_v:45.42 
n:39 mse_avg:3.21 mse_y:3.88 mse_u:1.99 mse_v:1.77 psnr_avg:43.06 psnr_y:42.24 psnr_u:45.13 psnr_v:45.66 
n:40 mse_avg:3.13 mse_y:3.77 mse_u:1.95 mse_v:1.76 psnr_avg:43.17 psnr_y:42.36 psnr_u:45.24 psnr_v:45.67 
n:41 mse_avg:3.08 mse_y:3.71 mse_u:1.90 mse_v:1.74 psnr_avg:43.24 psnr_y:42.43 psnr_u:45.34 psnr_v:45.74 
n:42 mse_avg:3.07 mse_y:3.70 mse_u:1.92 mse_v:1.70 psnr_avg:43.26 psnr_y:42.45 psnr_u:45.30 psnr_v:45.83 
n:43 mse_avg:3.05 mse_y:3.69 mse_u:1.89 mse_v:1.66 psnr_avg:43.29 psnr_y:42.47 psnr_u:45.36 psnr_v:45.94 
n:44 mse_avg:3.12 mse_y:3.77 mse_u:1.95 mse_v:1.69 psnr_avg:43.19 psnr_y:42.36 psnr_u:45.24 psnr_v:45.85 
n:45 mse_avg:3.13 mse_y:3.78 mse_u:1.95 mse_v:1.70 psnr_avg:43.18 psnr_y:42.35 psnr_u:45.22 psnr_v:45.83 
n:46 mse_avg:3.15 mse_y:3.81 mse_u:1.97 mse_v:1.72 psnr_avg:43.14 psnr_y:42.32 psnr_u:45.19 psnr_v:45.78 
n:47 mse_avg:3.49 mse_y:4.15 mse_u:2.33 mse_v:2.03 psnr_avg:42.70 psnr_y:41.95 psnr_u:44.46 psnr_v:45.06 
n:48 mse_avg:3.54 mse_y:4.21 mse_u:2.36 mse_v:2.08 psnr_avg:42.64 psnr_y:41.89 psnr_u:44.40 psnr_v:44.95 
n:49 mse_avg:3.46 mse_y:4.16 mse_u:2.21 mse_v:1.95 psnr_avg:42.74 psnr_y:41.94 psnr_u:44.69 psnr_v:45.24 
n:50 mse_avg:3.44 mse_y:4.12 mse_u:2.20 mse_v:1.96 psnr_avg:42.77 psnr_y:41.99 psnr_u:44.71 psnr_v:45.21 
n:51 mse_avg:3.50 mse_y:4.20 mse_u:2.22 mse_v:1.98 psnr_avg:42.69 psnr_y:41.89 psnr_u:44.66 psnr_v:45.16 
n:52 mse_avg:3.40 mse_y:4.14 mse_u:2.05 mse_v:1.79 psnr_avg:42.82 psnr_y:41.96 psnr_u:45.00 psnr_v:45.60 
n:53 mse_avg:3.41 mse_y:4.15 mse_u:2.10 mse_v:1.79 psnr_avg:42.80 psnr_y:41.96 psnr_u:44.92 psnr_v:45.61 
n:54 mse_avg:3.39 mse_y:4.11 mse_u:2.10 mse_v:1.82 psnr_avg:42.83 psnr_y:41.99 psnr_u:44.91 psnr_v:45.54 
n:55 mse_avg:3.41 mse_y:4.13 mse_u:2.12 mse_v:1.83 psnr_avg:42.80 psnr_y:41.97 psnr_u:44.87 psnr_v:45.51 
n:56 mse_avg:3.44 mse_y:4.15 mse_u:2.12 mse_v:1.88 psnr_avg:42.77 psnr_y:41.95 psnr_u:44.86 psnr_v:45.38 
n:57 mse_avg:3.43 mse_y:4.14 mse_u:2.13 mse_v:1.88 psnr_avg:42.78 psnr_y:41.96 psnr_u:44.85 psnr_v:45.39 
n:58 mse_avg:3.43 mse_y:4.14 mse_u:2.14 mse_v:1.90 psnr_avg:42.77 psnr_y:41.96 psnr_u:44.82 psnr_v:45.35 
n:59 mse_avg:3.49 mse_y:4.22 mse_u:2.15 mse_v:1.90 psnr_avg:42.70 psnr_y:41.88 psnr_u:44.81 psnr_v:45.35 
n:60 mse_avg:3.45 mse_y:4.17 mse_u:2.15 mse_v:1.88 psnr_avg:42.75 psnr_y:41.93 psnr_u:44.80 psnr_v:45.38 


    


    What causes this difference？

    


Navigation