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Autres articles (41)
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La file d’attente de SPIPmotion
28 novembre 2010, parUne file d’attente stockée dans la base de donnée
Lors de son installation, SPIPmotion crée une nouvelle table dans la base de donnée intitulée spip_spipmotion_attentes.
Cette nouvelle table est constituée des champs suivants : id_spipmotion_attente, l’identifiant numérique unique de la tâche à traiter ; id_document, l’identifiant numérique du document original à encoder ; id_objet l’identifiant unique de l’objet auquel le document encodé devra être attaché automatiquement ; objet, le type d’objet auquel (...) -
Contribute to translation
13 avril 2011You can help us to improve the language used in the software interface to make MediaSPIP more accessible and user-friendly. You can also translate the interface into any language that allows it to spread to new linguistic communities.
To do this, we use the translation interface of SPIP where the all the language modules of MediaSPIP are available. Just subscribe to the mailing list and request further informantion on translation.
MediaSPIP is currently available in French and English (...) -
Qu’est ce qu’un éditorial
21 juin 2013, parEcrivez votre de point de vue dans un article. Celui-ci sera rangé dans une rubrique prévue à cet effet.
Un éditorial est un article de type texte uniquement. Il a pour objectif de ranger les points de vue dans une rubrique dédiée. Un seul éditorial est placé à la une en page d’accueil. Pour consulter les précédents, consultez la rubrique dédiée.
Vous pouvez personnaliser le formulaire de création d’un éditorial.
Formulaire de création d’un éditorial Dans le cas d’un document de type éditorial, les (...)
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ffmpeg - How to bypass uneven segmentation with basic encoding ? [closed]
2 juin 2021, par valexttExample request :


ffmpeg -i 'input.mp4' -c:v libx264 -force_key_frames "expr:gte(t,n_forced*1)" -segment_time 20 -reset_timestamps 1 -f segment output%03d.mp4

If I use
-c:v libx264in the request, then the split time lasts for a long, but it works out correctly. In general, I am satisfied with the source codec, so I tried-c:v copy, so we do not change the codec, which makes the split process almost instantly, but the problem is, that the output segments are not 20 seconds each, but for example :
20.5 sec,18.5 sec,21 sec.
How to deal with it ? Why does the-c:v copymodify the split unevenly ?

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The SSIM values calculated using FFMPEG are not what I expected
18 mai 2020, par fd-alexerI'm trying to encode an m2ts (MPEG-2 Transport Stream) file to mp4 (H.264) and get the ssim value.

I did get some SSIM values, but the results were contrary to my expectations.


Are there wrong command options for ffmpeg ?



Encoding and SSIM calculation commands



# encode
$ ffmpeg -hide_banner -fflags +discardcorrupt -i input.m2ts \
 -c:v libx264 -crf <crf> -preset:v medium \
 -c:a copy -bsf:a aac_adtstoasc \
 output_ff_crf-<crf>.mp4

# calculate ssim
$ ffmpeg -hide_banner -i <a> -i <b> \
 -lavfi "[0:v]settb=AVTB,setpts=PTS-STARTPTS[main];[1:v]settb=AVTB,setpts=PTS-STARTPTS[ref];[main][ref]ssim" \
 -f null -
</b></a></crf></crf>


The results of the SSIM



(a) A=input.m2ts, B=input.m2ts, ssim=0.973266
(b) A=input.m2ts, B=output_ff_crf-0.mp4, ssim=0.813347
(c) A=input.m2ts, B=output_ff_crf-30.mp4, ssim=0.819897
(d) A=output_ff_crf-0.mp4, B=output_ff_crf-0.mp4, ssim=1.000000
(e) A=output_ff_crf-0.mp4, B=output_ff_crf-30.mp4, ssim=0.972911



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- (d)(e) : These are what I expected.
- (a) : The files are the same, but ssim≠1.
- (b)(c) : SSIMs with CRF=0 and CRF=30 have almost the same value, although the image quality is different.









In the case of HandBrakeCLI



To determine if there was a problem with input.m2ts, I ran HandBrakeCLI with almost the same parameters as ffmpeg.



# encode
HandBrakeCLI --verbose --format av_mp4 --encoder x264 --quality <crf> --x264-preset medium \
 --aencoder copy \
 --input input.m2ts --output output_hb_crf-<crf>.mp4

# calculate ssim (same as ffmpeg)
$ ffmpeg -hide_banner -i <a> -i <b> \
 -lavfi "[0:v]settb=AVTB,setpts=PTS-STARTPTS[main];[1:v]settb=AVTB,setpts=PTS-STARTPTS[ref];[main][ref]ssim" \
 -f null -
</b></a></crf></crf>


(b') A=input.m2ts, B=output_hb_crf-0.mp4, ssim=0.999999
(c') A=input.m2ts, B=output_hb_crf-30.mp4, ssim=0.972886
(d') A=output_hb_crf-0.mp4, B=output_hb_crf-0.mp4, ssim=1.000000
(e') A=output_hb_crf-0.mp4, B=output_hb_crf-30.mp4, ssim=0.972886



It's all as I expected. (although A is not ssim=1.0) 
Therefore, I don't see a problem with input.m2ts.



Informations about video files and tools



Results of the ffprobe



input.m2ts



[mpeg2video @ 0x5655577c1680] Invalid frame dimensions 0x0.
 Last message repeated 1 times
[mpegts @ 0x5655577bd080] start time for stream 2 is not set in estimate_timings_from_pts
[mpegts @ 0x5655577bd080] PES packet size mismatch
Input #0, mpegts, from 'input.m2ts':
 Duration: 00:30:02.68, start: 39593.392600, bitrate: 19019 kb/s
 Program 211
 Stream #0:0[0x140]: Video: mpeg2video (Main) ([2][0][0][0] / 0x0002), yuv420p(tv, bt709, top first), 1920x1080 [SAR 1:1 DAR 16:9], 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc
 Stream #0:1[0x141]: Audio: aac (LC) ([15][0][0][0] / 0x000F), 48000 Hz, stereo, fltp, 255 kb/s
 Stream #0:2[0x138]: Data: bin_data ([6][0][0][0] / 0x0006)
Unsupported codec with id 100359 for input stream 2



output_ff_crf-0.mp4



Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'output_ff_crf-0.mp4':
 Metadata:
 major_brand : isom
 minor_version : 512
 compatible_brands: isomiso2avc1mp41
 encoder : Lavf57.83.100
 Duration: 00:30:02.67, start: 0.000000, bitrate: 109301 kb/s
 Stream #0:0(und): Video: h264 (High 4:4:4 Predictive) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 109040 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc (default)
 Metadata:
 handler_name : VideoHandler
 Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 252 kb/s (default)
 Metadata:
 handler_name : SoundHandler



output_hb_crf-0.mp4



Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'output_hb_crf-0.mp4':
 Metadata:
 major_brand : mp42
 minor_version : 512
 compatible_brands: isomiso2avc1mp41
 creation_time : 2020-05-17T06:22:06.000000Z
 encoder : HandBrake 1.1.0 2018042400
 Duration: 00:30:02.22, start: 0.000000, bitrate: 109661 kb/s
 Stream #0:0(und): Video: h264 (High 4:4:4 Predictive) (avc1 / 0x31637661), yuv420p(tv, bt709), 1920x1080 [SAR 1:1 DAR 16:9], 109405 kb/s, 29.97 fps, 29.97 tbr, 90k tbn, 180k tbc (default)
 Metadata:
 creation_time : 2020-05-17T06:22:06.000000Z
 handler_name : VideoHandler
 Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 252 kb/s (default)
 Metadata:
 creation_time : 2020-05-17T06:22:06.000000Z
 handler_name : Stereo



Tools



version



- 

- ffmpeg : 3.4.6-0ubuntu0.18.04.1
- HandBrakeCLI : 1.1.0







ldd



$ ldd /usr/bin/ffmpeg
...
libx264.so.152 => /usr/lib/x86_64-linux-gnu/libx264.so.152 (0x00007efbf1f33000)
...

$ ldd /usr/bin/HandBrakeCLI
...
libx264.so.152 => /usr/lib/x86_64-linux-gnu/libx264.so.152 (0x00007efbfb38f000)
...



ffmpeg and HandBrakeCLI are using the same libx264.


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On concatinating two videos in FFmpeg, the output video is far longer than expected
15 août 2019, par Ngo Van PhucI want to ask about FFmpeg.
- Video A (time : 00:31:51 - 1280x720)
- Video B (time : 00:00:22 - 1280x720)
- output video : (time : 01:20:38)
The code I use :
ffmpeg -f concat -i file-list.txt -c copy outputfile.mp4I hear people say, need to encode videos, How to encode video ?
please help me.
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