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Autres articles (112)
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Les autorisations surchargées par les plugins
27 avril 2010, parMediaspip core
autoriser_auteur_modifier() afin que les visiteurs soient capables de modifier leurs informations sur la page d’auteurs -
Encoding and processing into web-friendly formats
13 avril 2011, parMediaSPIP automatically converts uploaded files to internet-compatible formats.
Video files are encoded in MP4, Ogv and WebM (supported by HTML5) and MP4 (supported by Flash).
Audio files are encoded in MP3 and Ogg (supported by HTML5) and MP3 (supported by Flash).
Where possible, text is analyzed in order to retrieve the data needed for search engine detection, and then exported as a series of image files.
All uploaded files are stored online in their original format, so you can (...) -
Emballe médias : à quoi cela sert ?
4 février 2011, parCe plugin vise à gérer des sites de mise en ligne de documents de tous types.
Il crée des "médias", à savoir : un "média" est un article au sens SPIP créé automatiquement lors du téléversement d’un document qu’il soit audio, vidéo, image ou textuel ; un seul document ne peut être lié à un article dit "média" ;
Sur d’autres sites (5171)
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Use data to develop impactful video content
28 septembre 2021, par Ben Erskine — Analytics Tips, Plugins -
ffmpeg, /dev/video0, -f decklink
20 mars 2019, par Camille GoudeseuneI’m trying to capture video from a PCI card, the Blackmagic DeckLink Mini Recorder, via ffmpeg, on a headless host running Ubuntu 18.04.2 LTS, hopefully with a command like
ffmpeg -f decklink -i /dev/video0 ...
How can I make that work ? I have two obstacles.
No /dev/video0
ffmpeg -i /dev/video0 ...
fails :/dev/video0: No such device or address
.
v4l2-ctl --list-devices
fails with the same error message.I built /dev/video0, and it looks okay :
mknod /dev/video0 c 81 0
chown root.video /dev/video0
chmod g+rw /dev/video0To compare this file with a working one, I ran
strace cat /dev/video0
on this host, and on another host (Ubuntu 14) with a working /dev/video0. The outputs began to differ here (good, then bad) :fstat(1, {st_mode=S_IFREG|0644, st_size=0, ...}) = 0
open("/dev/video0", O_RDONLY) = 3
fstat(3, {st_mode=S_IFCHR|0660, st_rdev=makedev(81, 0), ...}) = 0
fadvise64(3, 0, 0, POSIX_FADV_SEQUENTIAL) = 0
----
fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 0), ...}) = 0
openat(AT_FDCWD, "/dev/video0", O_RDONLY) = -1 ENXIO (No such device or address)So /dev/video0 is broken at a level lower than ffmpeg or v4l2 or even cat.
On Ubuntu 14,
man 8 MAKEDEV
suggests that the error message means that "the kernel does not have the driver configured or loaded."This Ubuntu 18 host lacks that manpage, but it does have a few
/snap/core/*/sbin/MAKEDEV
, all the same, so I tried/snap/core/6350/sbin/MAKEDEV -n -v video
It would have created over a hundred devices videoXX, radioXX, vtxXX, vbiXX. Those devices didn’t exist yet, so it seemed harmless to try it.
rm /dev/video0; /snap/core/6350/sbin/MAKEDEV video
That rebuilt /dev/video0, but "No such device" remains, from cat or ffmpeg.
No decklink
ffmpeg -f decklink ...
fails withUnknown input format: 'decklink'
.Neither black nor deck nor link is mentioned by
ffmpeg -devices
(fbdev, lavfi, oss, v4l2) andffmpeg -formats
(about 350), either for Ubuntu’s own version 3.4.4-0ubuntu0.18.04.1, or for version N-93330-g7ff89574c7 compiled from source on 2019 Mar 13 :git clone https://git.ffmpeg.org/ffmpeg.git ffmpeg
cd ffmpeg
./configure --enable-nonfree --disable-doc --disable-w32threads --enable-pthreads(Although
./configure --help
mentions--enable-decklink
, using that yielded "ERROR : DeckLinkAPI.h not found."updatedb && locate DeckLinkAPI.h
finds no file with that name, either.)The DeckLink PCI card is recognized by
hwinfo
andlspci
.lsmod
reports the loaded modulesblackmagic
andblackmagic_io
.Maybe the PCI card is installed ok, but ffmpeg just can’t reach it because I can’t configure it for that.
Edit : Rebooting didn’t fix anything.
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FFMPEG stereo track stops capturing at random times during a capture session
26 mai 2022, par mrwassenI am currently working on building a workflow to capture and archive a large stash of family and friends PAL and NTSC VHS tapes. The hardware setup is as follows :


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- JVC HR-7860S VCR
- s-video / RCA audio >
- ADVC-3000 converter
- SDI / BNC cable >
- Blackmagic Decklink Mini Recorder 4K PCIe card
- installed in a fairly hi-spec windows machine : AMD Ryzen 9 5900X 3.7 Ghz base 12 core, GEFORCE RTX 3060 12 gB, 32 gB ram














The plan is to capture to lossless AVI, then drop into an NLE (Vegas Pro v.16) to do a minimal amount of cleanup / trimming, then render to a more compressed video format (TBD) for upload to AWS S3 accessible through a family website.


The issue I am having is that when I run the capture using ffmpeg/directshow e.g. for a perfectly fine 90 min. PAL tape, at some random point of time during the capture one of the 2 stereo channels just stops capturing. This has happened with all of the tapes I have tested so far, and it happens at different times during the same video. I have examined the frames surrounding points in time when this happens, and it doesn't correlate to any transitions or jitter, but often just randomly in the middle of a perfectly smooth scene. Once the one channel stops capturing it never starts back up again during that capture session.


The ADVC-3000 and the VCR are both showing both stereo channels playing normally throughout the capture. The windows machine running the capture hardly breaks a sweat at any time, and the transfer easily keeps up constantly showing a speed = 1x which I assume means nothing lagging. Also there are no video/audio sync issues at any point in time even towards the end of long tapes e.g. 90 mins.


I am fairly new at ffmpeg, so I have spent extensive amounts of time reading up on forum posts and experimenting and have ended up with the following syntax :


ffmpeg -y -f dshow -rtbufsize 2000M -i video="Blackmagic WDM Capture":audio="Blackmagic WDM Capture" -codec:v v210 -pix_fmt yuv422p -codec:a pcm_s16le -b:a 128k -t 02:00:00 -r 25 -threads 4 -maxrate 2500k -filter:a "volume=1.5" output_v210_audio.avi



The capture runs without a single dropped frame, the only error I am getting when launching (and perhaps this is a smoking gun ?) is :




"Non-monotonous DTS in output stream 0:1 ; previous : 0, current : -30 ;
changing to 1. This may result in incorrect timestamps in the output
file."




I have tried to troubleshoot this in the hopes that it is tied to my issue but so far without luck.


Hoping somebody can help correct or modify my command line or perhaps other ideas to help resolve the issue.