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Rennes Emotion Map 2010-11
19 octobre 2011, par
Mis à jour : Juillet 2013
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Des sites réalisés avec MediaSPIP
2 mai 2011, parCette page présente quelques-uns des sites fonctionnant sous MediaSPIP.
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Participer à sa documentation
10 avril 2011La documentation est un des travaux les plus importants et les plus contraignants lors de la réalisation d’un outil technique.
Tout apport extérieur à ce sujet est primordial : la critique de l’existant ; la participation à la rédaction d’articles orientés : utilisateur (administrateur de MediaSPIP ou simplement producteur de contenu) ; développeur ; la création de screencasts d’explication ; la traduction de la documentation dans une nouvelle langue ;
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Submit enhancements and plugins
13 avril 2011If you have developed a new extension to add one or more useful features to MediaSPIP, let us know and its integration into the core MedisSPIP functionality will be considered.
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Sur d’autres sites (5220)
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Record video stream in rust
19 novembre 2024, par El_LocoI have bought a stereo camera with global shutter and a frame rate of at most 120 fps. https://www.amazon.com/dp/B0D8T3ZSL4?ref_=pe_386300_442618370_TE_sc_as_ri_0#


My next step is to write a program that can show and record a video with desired fps and resolution.


use opencv::{
 core, highgui,
 prelude::*,
 videoio::{self, VideoCapture},
 Result,
};

fn open_camera() -> Result<videocapture> {
 let capture = videoio::VideoCapture::new(2, videoio::CAP_ANY)?;
 return Ok(capture);
}
fn main() -> Result<()> {
 let window = "video capture";
 highgui::named_window(window, highgui::WINDOW_AUTOSIZE)?;
 let mut cam = open_camera()?;
 let opened = videoio::VideoCapture::is_opened(&cam)?;
 if !opened {
 panic!("Unable to open default camera!");
 }
 let width = 3200.0;
 let height = 1200.0;
 cam.set(videoio::CAP_PROP_FRAME_WIDTH, width)?;
 cam.set(videoio::CAP_PROP_FRAME_HEIGHT, height)?;

 // Set the frame rate (FPS)
 let fps = 60.0;
 
 let fourcc = videoio::VideoWriter::fourcc('M', 'J', 'P', 'G')?;
 let mut writer = videoio::VideoWriter::new(
 "video_output.avi",
 fourcc,
 fps,
 core::Size::new(width as i32, height as i32),
 true,
 )?;

 if !writer.is_opened()? {
 println!("Error: Could not open the video writer.");
 }

 let mut frame = core::Mat::default();
 let mut ctr = 0;
 while cam.read(&mut frame)? {
 if frame.empty() {
 break;
 }
 writer.write(&frame)?;
 highgui::imshow(window, &frame)?;
 
 let key = highgui::wait_key(1)?;
 if key > 0 {
 break;
 }
 ctr += 1;
 if ctr == 600 {
 break;
 }
 }
 cam.release()?;
 writer.release()?;
 Ok(())
}
</videocapture>

When I run this code the frame rate is terrible. Like 1 fps or something. For debugging I tried to run in cheese. There I got 30 fps with full resolution
3200x1200. But I cannot change the fps to 60 fps what I can see.

Then I tried to capture a video using ffmpeg :


ffmpeg -f v4l2 -framerate 60 -video_size 3200x1200 -i /dev/video2 output.mp4

With the following output :


[video4linux2,v4l2 @ 0x5a72cbbd1400] The driver changed the time per frame from 1/60 to 1/2
Input #0, video4linux2,v4l2, from '/dev/video2':
 Duration: N/A, start: 2744.250608, bitrate: 122880 kb/s
 Stream #0:0: Video: rawvideo (YUY2 / 0x32595559), yuyv422, 3200x1200, 122880 kb/s, 2 fps, 2 tbr, 1000k tbn
File 'output.mp4' already exists. Overwrite? [y/N]


The frame rate is lowered to 2 fps.


Then I tried to run
v4l2-ctl --list-formats-ext -d 2with the following output :

ioctl: VIDIOC_ENUM_FMT
 Type: Video Capture

 [0]: 'MJPG' (Motion-JPEG, compressed)
 Size: Discrete 3200x1200
 Interval: Discrete 0.017s (60.000 fps)
 Interval: Discrete 0.033s (30.000 fps)
 Interval: Discrete 0.040s (25.000 fps)
 Interval: Discrete 0.050s (20.000 fps)
 Interval: Discrete 0.067s (15.000 fps)
 Interval: Discrete 0.100s (10.000 fps)
 Size: Discrete 2560x720
 Interval: Discrete 0.017s (60.000 fps)
 Interval: Discrete 0.033s (30.000 fps)
 Interval: Discrete 0.040s (25.000 fps)
 Interval: Discrete 0.050s (20.000 fps)
 Interval: Discrete 0.067s (15.000 fps)
 Interval: Discrete 0.100s (10.000 fps)
 Size: Discrete 1600x600
 Interval: Discrete 0.008s (120.000 fps)
 Interval: Discrete 0.017s (60.000 fps)
 Interval: Discrete 0.033s (30.000 fps)
 Interval: Discrete 0.040s (25.000 fps)
 Interval: Discrete 0.050s (20.000 fps)
 Interval: Discrete 0.067s (15.000 fps)


I then tried to open the camera using
qv4land there it seemed to work. Does not seem like I can record a video though.

I am using Rust to learn. I want to be able to programmatically be able to record a video somehow and then do computer vision. The easiest would be to do it in Rust. But other solutions are ok.


Edit
I have found some more this morning :


v4l2-ctl -d 2 --list-formats-ext
ioctl: VIDIOC_ENUM_FMT
 Type: Video Capture

 [0]: 'MJPG' (Motion-JPEG, compressed)
 Size: Discrete 3200x1200
 Interval: Discrete 0.017s (60.000 fps)
 Interval: Discrete 0.033s (30.000 fps)
 Interval: Discrete 0.040s (25.000 fps)
 Interval: Discrete 0.050s (20.000 fps)
 Interval: Discrete 0.067s (15.000 fps)
 Interval: Discrete 0.100s (10.000 fps)

 [1]: 'YUYV' (YUYV 4:2:2)
 Size: Discrete 3200x1200
 Interval: Discrete 0.500s (2.000 fps)
 Size: Discrete 2560x720
 Interval: Discrete 0.500s (2.000 fps)
 Size: Discrete 1600x600
 Interval: Discrete 0.100s (10.000 fps)


I also found here that order of flags was important for
ffmpeg. Running this I can actually record a video with 60 fps :

ffmpeg -framerate 60 -f v4l2 -video_size 3200x1200 -input_format mjpeg -i /dev/video2 output.avi

A drawback is that the images does not look very sharp. You can clearly see the pixels. (I am new to video formats etc as well. Before it has just worked.)


If I change from
avitomkvit is slow again.

In the link above I also saw a suggestion to first do :


ffmpeg -framerate 60 -f v4l2 -video_size 3200x1200 -input_format mjpeg -i /dev/video2 -c copy mjpeg.mkv

and then :


ffmpeg -i mjpeg.mkv -c:v libx264 -crf 23 -preset medium -pix_fmt yuv420p out.mkv

which worked. But I am not sure those flags are ideal for the camera I have. I think it is a good start to make it run as expected using command line and ffmpeg. So I know what format to use and that it actually works as intended before doing it programmatically.


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Can I convert a django video upload from a form using ffmpeg before storing the video ?
5 mai 2014, par GetItDoneI’ve been stuck for weeks trying to use ffmpeg to convert user uploaded videos to flv. I use heroku to host my website, and store my static and media files on amazon S3 with s3boto. The initial video file will upload fine, however when I retrieve the video and run a celery task (in the same view where the initial video file is uploaded), the new file won’t store on S3. I’ve been trying to get this to work for over a month, with no luck, and really no good resources available for learning how to do this, so I figure maybe if I can get the ffmpeg task to run before storing the video I may be able to get it to work. Unfortunately I’m still not a very advanced at python (or django), so I don’t even know if/how this is possible. Anyone have any ideas ? I am willing to use any solution at this point no matter how ugly, as long as it successfully takes video uploads and converts to flv using ffmpeg, with the resulting file being stored on S3. It doesn’t seem that my situation is very common, because no matter where I look, I cannot find a solution that explains what I should be trying to do. Therefore I will be very appreciative of any guidance. Thanks. My relevant code follows :
#models.py
def content_file_name(instance, filename):
ext = filename.split('.')[-1]
new_file_name = "remove%s.%s" % (uuid.uuid4(), ext)
return '/'.join(['videos', instance.teacher.username, new_file_name])
class BroadcastUpload(models.Model):
title = models.CharField(max_length=50, verbose_name=_('Title'))
description = models.TextField(max_length=100, verbose_name=_('Description'))
teacher = models.ForeignKey(User, null=True, blank=True, related_name='teacher')
created_date = models.DateTimeField(auto_now_add=True)
video_upload = models.FileField(upload_to=content_file_name)
flvfilename = models.CharField(max_length=100, null=True, blank=True)
videothumbnail = models.CharField(max_length=100, null=True, blank=True)
#tasks.py
@task(name='celeryfiles.tasks.convert_flv')
def convert_flv(video_id):
video = BroadcastUpload.objects.get(pk=video_id)
print "ID: %s" % video.id
id = video.id
print "VIDEO NAME: %s" % video.video_upload.name
teacher = video.teacher
print "TEACHER: %s" % teacher
filename = video.video_upload
sourcefile = "%s%s" % (settings.MEDIA_URL, filename)
vidfilename = "%s_%s.flv" % (teacher, video.id)
targetfile = "%svideos/flv/%s" % (settings.MEDIA_URL, vidfilename)
ffmpeg = "ffmpeg -i %s %s" % (sourcefile, vidfilename)
try:
ffmpegresult = subprocess.call(ffmpeg)
#also tried separately with following line:
#ffmpegresult = commands.getoutput(ffmpeg)
print "---------------FFMPEG---------------"
print "FFMPEGRESULT: %s" % ffmpegresult
except Exception as e:
ffmpegresult = None
print("Failed to convert video file %s to %s" % (sourcefile, targetfile))
print(traceback.format_exc())
video.flvfilename = vidfilename
video.save()
@task(name='celeryfiles.tasks.ffmpeg_image')
def ffmpeg_image(video_id):
video = BroadcastUpload.objects.get(pk=video_id)
print "ID: %s" %video.id
id = video.id
print "VIDEO NAME: %s" % video.video_upload.name
teacher = video.teacher
print "TEACHER: %s" % teacher
filename = video.video_upload
sourcefile = "%s%s" % (settings.MEDIA_URL, filename)
imagefilename = "%s_%s.png" % (teacher, video.id)
thumbnailfilename = "%svideos/flv/%s" % (settings.MEDIA_URL, thumbnailfilename)
grabimage = "ffmpeg -y -i %s -vframes 1 -ss 00:00:02 -an -vcodec png -f rawvideo -s 320x240 %s" % (sourcefile, thumbnailfilename)
try:
videothumbnail = subprocess.call(grabimage)
#also tried separately following line:
#videothumbnail = commands.getoutput(grabimage)
print "---------------IMAGE---------------"
print "VIDEOTHUMBNAIL: %s" % videothumbnail
except Exception as e:
videothumbnail = None
print("Failed to convert video file %s to %s" % (sourcefile, thumbnailfilename))
print(traceback.format_exc())
video.videothumbnail = imagefilename
video.save()
#views.py
def upload_broadcast(request):
if request.method == 'POST':
form = BroadcastUploadForm(request.POST, request.FILES)
if form.is_valid():
upload=form.save()
video_id = upload.id
image_grab = ffmpeg_image.delay(video_id)
video_conversion = convert_flv.delay(video_id)
return HttpResponseRedirect('/current_classes/')
else:
form = BroadcastUploadForm(initial={'teacher': request.user,})
return render_to_response('videos/create_video.html', {'form': form,}, context_instance=RequestContext(request))
#settings.py
DEFAULT_FILE_STORAGE = 'myapp.s3utils.MediaRootS3BotoStorage'
DEFAULT_S3_PATH = "media"
STATICFILES_STORAGE = 'myapp.s3utils.StaticRootS3BotoStorage'
STATIC_S3_PATH = "static"
AWS_STORAGE_BUCKET_NAME = 'my_bucket'
CLOUDFRONT_DOMAIN = 'domain.cloudfront.net'
AWS_ACCESS_KEY_ID = 'MY_KEY_ID'
AWS_SECRET_ACCESS_KEY = 'MY_SECRET_KEY'
MEDIA_ROOT = '/%s/' % DEFAULT_S3_PATH
MEDIA_URL = 'http://%s/%s/' % (CLOUDFRONT_DOMAIN, DEFAULT_S3_PATH)
...
#s3utils.py
from storages.backends.s3boto import S3BotoStorage
from django.utils.functional import SimpleLazyObject
StaticRootS3BotoStorage = lambda: S3BotoStorage(location='static')
MediaRootS3BotoStorage = lambda: S3BotoStorage(location='media')I can add any other info if needed to help me solve my problem.
-
hevc : a much faster implementation of intra prediction (up to 1s on
13 mai 2014, par Mickaël Raulet
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