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Autres articles (52)
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Mise à jour de la version 0.1 vers 0.2
24 juin 2013, parExplications des différents changements notables lors du passage de la version 0.1 de MediaSPIP à la version 0.3. Quelles sont les nouveautés
Au niveau des dépendances logicielles Utilisation des dernières versions de FFMpeg (>= v1.2.1) ; Installation des dépendances pour Smush ; Installation de MediaInfo et FFprobe pour la récupération des métadonnées ; On n’utilise plus ffmpeg2theora ; On n’installe plus flvtool2 au profit de flvtool++ ; On n’installe plus ffmpeg-php qui n’est plus maintenu au (...) -
Personnaliser en ajoutant son logo, sa bannière ou son image de fond
5 septembre 2013, parCertains thèmes prennent en compte trois éléments de personnalisation : l’ajout d’un logo ; l’ajout d’une bannière l’ajout d’une image de fond ;
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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
Sur d’autres sites (10383)
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How can I correctly provide a fake webcam input to Chrome ?
30 août 2018, par doppelgreenerI’m trying to run end-to-end testing in Chrome for a product that requires a webcam feed halfway through to operate. From what I understand this means providing a fake webcam video to Chrome using the
--use-file-for-fake-video-capture="/path/to/video.y4m"command line argument. It will then use that as a webcam video.However, no matter what y4m file I provide, I get the following error from Chrome running under these conditions :
DOMException: Could not start video source
{
code: 0,
message: "Could not start video source",
name: "NotReadableError"
}Notably I can provide an audio file just fine using
--use-file-for-fake-audio-captureand Chrome will work with it well. The video has been my sticking point.This error comes out of the following straightforward mediaDevices request :
navigator.mediaDevices.getUserMedia({ video: true, audio: true })
.then(data => {
// do stuff
})
.catch(err => {
// oh no!
});(This always hits the “oh no !” branch when a video file is provided.)
What I’ve tried so far
I’ve been running Chrome with the following command line arguments (newlines added for readability), and I’m using a Mac hence the
opencommand :open -a "Google Chrome" --args
--disable-gpu
--use-fake-device-for-media-stream
--use-file-for-fake-video-capture="~/Documents/mock/webcam.y4m"
--use-file-for-fake-audio-capture="~/Documents/mock/microphone.wav"webcam.y4mandmicrophone.wavwere generated from a video file I recorded.I first recorded a twenty-second mp4 video using my browser’s MediaRecorder, downloaded the result, and converted it using the following command line commands :
ffmpeg -y -i original.mp4 -f wav -vn microphone.wav
ffmpeg -y -i original.mp4 webcam.y4mWhen this didn’t work, I tried the same using a twenty-second movie file I recorded in Quicktime :
ffmpeg -y -i original.mov -f wav -vn microphone.wav
ffmpeg -y -i original.mov webcam.y4mWhen that also failed, I went straight to the Chromium file that explains fake video capture, went to the example y4m file list it provided, and downloaded the grandma file and provided that as a command line argument to Chrome instead :
open -a "Google Chrome" --args
--disable-gpu
--use-fake-device-for-media-stream
--use-file-for-fake-video-capture="~/Documents/mock/grandma_qcif.y4m"
--use-file-for-fake-audio-capture="~/Documents/mock/microphone.wav"Chrome provides me with the exact same error in all of these situations.
The only time Chrome doesn’t error out with that mediaDevices request is when I omit the video completely :
open -a "Google Chrome" --args
--disable-gpu
--use-fake-device-for-media-stream
--use-file-for-fake-audio-capture="~/Documents/mock/microphone.wav"Accounting for C420mpeg2
TestRTC suggests Chrome will “crash” if I give it a
C420mpeg2file, and recommends that simply replacing the metadata fixes the issue. Indeed the video file I generate from ffmpeg gives me the following header :YUV4MPEG2 W1280 H720 F30:1 Ip A1:1 C420mpeg2 XYSCSS=420MPEG2Chrome doesn’t actually crash when run with this file, I just get the error above. If I edit the video file to the following header though per TestRTC’s recommendations I get the same situation :
YUV4MPEG2 W1280 H720 F30:1 Ip A1:1 C420 XYSCSS=420MPEG2The video file still gives me the above error in these conditions.
What can/should I do ?
How should I be providing a video file to Chrome for this command line argument ?
How should I be recording or creating the video file ?
How should I convert it to y4m ?
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How to compress webcam videos recorded by html5 MediaRecorder api ?
19 mai 2017, par JasonYI successfully recorded my webcam using MediaRecorder api and the resulting filesizes seemed far too big for their quality.
For example, for an 8 second video that was 480x640 I got a 1mB file size. That does not seem right.
My code to record()
navigator.mediaDevices.getUserMedia({video: true, audio: true})
.then(function(stream){
var options = {
mimeType : "video/webm;codecs=vp9"
//I don't set bitrate here even if I do the quality is too bad
}
var media_recorder = new MediaRecorder(media_stream, options);
var recorded_data = [];
media_recorder.ondataavailable = function(e){
recorded_data.push(e.data);
}
media_recorder.onstop = function(e){
recorded_data.push(e.data);
var recorded_blob = new Blob(recorded_data, { 'type' : 'video/webm; codecs=vp9' });
var recorded_video_url = window.URL.createObjectURL(recorded_blob);
//here I write some code to download the blob from this url through a href
}
})The file obtained by this method is unreasonably large which makes me wonder if it was even compressed when encoded by VP9 ? A 7 second video is about 870kB !
Inspecting the file with a mediainfo tool gives me
General
Count : 323
Count of stream of this kind : 1
Kind of stream : General
Kind of stream : General
Stream identifier : 0
Count of video streams : 1
Count of audio streams : 1
Video_Format_List : VP9
Video_Format_WithHint_List : VP9
Codecs Video : V_VP9
Video_Language_List : English
Audio_Format_List : Opus
Audio_Format_WithHint_List : Opus
Audio codecs : Opus
Audio_Language_List : English
Complete name : recorded_video.webm
File name : recorded_video
File extension : webm
Format : WebM
Format : WebM
Format/Url : http://www.webmproject.org/
Format/Extensions usually used : webm
Commercial name : WebM
Format version : Version 2
Internet media type : video/webm
Codec : WebM
Codec : WebM
Codec/Url : http://www.webmproject.org/
Codec/Extensions usually used : webm
File size : 867870
File size : 848 KiB
File size : 848 KiB
File size : 848 KiB
File size : 848 KiB
File size : 847.5 KiB
File last modification date : UTC 2017-05-19 05:48:00
File last modification date (local) : 2017-05-19 17:48:00
Writing application : Chrome
Writing application : Chrome
Writing library : Chrome
Writing library : Chrome
IsTruncated : Yes
Video
Count : 332
Count of stream of this kind : 1
Kind of stream : Video
Kind of stream : Video
Stream identifier : 0
StreamOrder : 1
ID : 2
ID : 2
Unique ID : 62101435245162993
Format : VP9
Commercial name : VP9
Codec ID : V_VP9
Codec ID/Url : http://www.webmproject.org/
Codec : V_VP9
Codec : V_VP9
Width : 640
Width : 640 pixels
Height : 480
Height : 480 pixels
Pixel aspect ratio : 1.000
Display aspect ratio : 1.333
Display aspect ratio : 4:3
Frame rate mode : VFR
Frame rate mode : Variable
Language : en
Language : English
Language : English
Language : en
Language : eng
Language : en
Default : Yes
Default : Yes
Forced : No
Forced : No
Audio
Count : 272
Count of stream of this kind : 1
Kind of stream : Audio
Kind of stream : Audio
Stream identifier : 0
StreamOrder : 0
ID : 1
ID : 1
Unique ID : 32224324715799545
Format : Opus
Format/Url : http://opus-codec.org/
Commercial name : Opus
Internet media type : audio/opus
Codec ID : A_OPUS
Codec ID/Url : http://opus-codec.org
Codec : Opus
Codec : Opus
Codec/Family : PCM
Channel(s) : 1
Channel(s) : 1 channel
Channel positions : Front: C
Channel positions : 1/0/0
Sampling rate : 48000
Sampling rate : 48.0 KHz
Compression mode : Lossy
Compression mode : Lossy
Delay : 718
Delay : 718ms
Delay : 718ms
Delay : 718ms
Delay : 00:00:00.718
Delay, origin : Container
Delay, origin : Container
Language : en
Language : English
Language : English
Language : en
Language : eng
Language : en
Default : Yes
Default : Yes
Forced : No
Forced : NoWhat did I do wrong ? Do I have to re-encode it after the chunks get appended ? Is there some attribute I’m missing ? VP9 is supposed to reduce file sizes drastically.
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How to compress webcam videos recorded by html5 MediaRecorder api ?
25 mai 2017, par JasonYI successfully recorded my webcam using MediaRecorder api and the resulting filesizes seemed far too big for their quality.
For example, for an 8 second video that was 480x640 I got a 1mB file size. That does not seem right.
My code to record()
navigator.mediaDevices.getUserMedia({video: true, audio: true})
.then(function(stream){
var options = {
mimeType : "video/webm;codecs=vp9"
//I don't set bitrate here even if I do the quality is too bad
}
var media_recorder = new MediaRecorder(media_stream, options);
var recorded_data = [];
media_recorder.ondataavailable = function(e){
recorded_data.push(e.data);
}
media_recorder.onstop = function(e){
recorded_data.push(e.data);
var recorded_blob = new Blob(recorded_data, { 'type' : 'video/webm; codecs=vp9' });
var recorded_video_url = window.URL.createObjectURL(recorded_blob);
//here I write some code to download the blob from this url through a href
}
})The file obtained by this method is unreasonably large which makes me wonder if it was even compressed when encoded by VP9 ? A 7 second video is about 870kB !
Inspecting the file with a mediainfo tool gives me
General
Count : 323
Count of stream of this kind : 1
Kind of stream : General
Kind of stream : General
Stream identifier : 0
Count of video streams : 1
Count of audio streams : 1
Video_Format_List : VP9
Video_Format_WithHint_List : VP9
Codecs Video : V_VP9
Video_Language_List : English
Audio_Format_List : Opus
Audio_Format_WithHint_List : Opus
Audio codecs : Opus
Audio_Language_List : English
Complete name : recorded_video.webm
File name : recorded_video
File extension : webm
Format : WebM
Format : WebM
Format/Url : http://www.webmproject.org/
Format/Extensions usually used : webm
Commercial name : WebM
Format version : Version 2
Internet media type : video/webm
Codec : WebM
Codec : WebM
Codec/Url : http://www.webmproject.org/
Codec/Extensions usually used : webm
File size : 867870
File size : 848 KiB
File size : 848 KiB
File size : 848 KiB
File size : 848 KiB
File size : 847.5 KiB
File last modification date : UTC 2017-05-19 05:48:00
File last modification date (local) : 2017-05-19 17:48:00
Writing application : Chrome
Writing application : Chrome
Writing library : Chrome
Writing library : Chrome
IsTruncated : Yes
Video
Count : 332
Count of stream of this kind : 1
Kind of stream : Video
Kind of stream : Video
Stream identifier : 0
StreamOrder : 1
ID : 2
ID : 2
Unique ID : 62101435245162993
Format : VP9
Commercial name : VP9
Codec ID : V_VP9
Codec ID/Url : http://www.webmproject.org/
Codec : V_VP9
Codec : V_VP9
Width : 640
Width : 640 pixels
Height : 480
Height : 480 pixels
Pixel aspect ratio : 1.000
Display aspect ratio : 1.333
Display aspect ratio : 4:3
Frame rate mode : VFR
Frame rate mode : Variable
Language : en
Language : English
Language : English
Language : en
Language : eng
Language : en
Default : Yes
Default : Yes
Forced : No
Forced : No
Audio
Count : 272
Count of stream of this kind : 1
Kind of stream : Audio
Kind of stream : Audio
Stream identifier : 0
StreamOrder : 0
ID : 1
ID : 1
Unique ID : 32224324715799545
Format : Opus
Format/Url : http://opus-codec.org/
Commercial name : Opus
Internet media type : audio/opus
Codec ID : A_OPUS
Codec ID/Url : http://opus-codec.org
Codec : Opus
Codec : Opus
Codec/Family : PCM
Channel(s) : 1
Channel(s) : 1 channel
Channel positions : Front: C
Channel positions : 1/0/0
Sampling rate : 48000
Sampling rate : 48.0 KHz
Compression mode : Lossy
Compression mode : Lossy
Delay : 718
Delay : 718ms
Delay : 718ms
Delay : 718ms
Delay : 00:00:00.718
Delay, origin : Container
Delay, origin : Container
Language : en
Language : English
Language : English
Language : en
Language : eng
Language : en
Default : Yes
Default : Yes
Forced : No
Forced : NoWhat did I do wrong ? Do I have to re-encode it after the chunks get appended ? Is there some attribute I’m missing ? VP9 is supposed to reduce file sizes drastically.
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