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• Anomalie #3377 : #ACTION_FORMULAIRE incomplet avec une install en sous répertoire

  25 janvier 2015, par Nicolas Dorigny

  Précision : le bug apparait en urls propres, pas en urls simples.

  C’est lié à priori lié à urls_decoder_url(), qui elle même appelle urls_propres_dist() pour décoder l’url en cours, en lui passant l’url complète (avec le sous répertoire).
  urls_propres_dist() ne retrouve pas l’objet correspondant et renvoie un contexte 404 au lieu de id_article / article.

  Je ne sais pas aller plus loin, il y a peut être un nettoyage d’url à faire quelque part pour filtrer le sous répertoire (?)

• How can I capture low resolution video on Android reliably across a range of devices ?

  26 octobre 2015, par MisterMat

  Hello Android video experts :)

  I am developing an Android application which allows the user to capture video and upload it to a remote server (it’s more involved than that but the rest of the app is not important). Because of the upload requirement, it is important that the video is of a reasonable size, so not super high resolution. Let’s say a max of 680x480 or 10Mb/minute. This is no problem on Apple devices.

  I have had what can only be described as a complete nightmare trying to capture video at a reasonably low bitrate reliably across a range of Android devices.

  As I understand it there are two ways of capturing video on Android :

  1) Using the Media Recorder/Camera API

  2) Using an Intent to open the cameras video capture application

  Option 1) gives the most flexibility and allows us to easily change the capture resolution. However the Android Camera API is NOT reliable across a range of devices, and I have very good information (including from someone who liaised with Google on this issue) that if you capture video using this API then it will crash on a good 50% of the devices out there. There is a reason that Zoom Camera FX uses an Intent for video capture. Zoom Camera (different app) seems to use Media Recorder, but has lots of bad reviews for video crashing or not working.

  Option 2) works well across a range of devices, as it uses the in built application on the device. The trouble is you have no control whatsoever on the resolution, there is a quality hint on the Intent but the camera app will normally ignore this. My Samsung Galaxy S3 records video by default at about 2Mb/s. This is way too high resolution. The built in application can of course change the resolution, but this relies on action by the user which is difficult to control.

  I understand that I could use a library such as ffmpeg to change the resolution of the video after capture. However this requires me to compile the library for Android, and also I have been informed that in order to legally use the decode/encode codecs on the device you have to pay license fees that amount to about $1 per copy of the app. Since this app will be free to use, this is not an option.

  So that’s where I’m at. I’ve searched long and high for answers, but I can’t figure out how to capture low resolution video reliably using Android.

  Any help very much appreciated !

  Matthew

• Synchronizing screencasting (ffmpeg) and capturing from the webcam (OpenCV)

  24 avril 2013, par lyuba

  As from my previous questions, I am trying to build a simple eye tracker. Decided to start from a Linux version (run Ubuntu).

  To complete this task one should organize screencasting and webcam capturing in such way that frames from both streams exactly match each other and there is the same number of frames in each of them totally.

  Screencasting fps fully depends on the camera's fps, so each time we get the image from the webcam we can potentially grab a screen frame and stay happy. However, all the tools for the fast screencasting, like ffmpeg, for example, return the .avi file as the result and require the fps already known to be started.

  From the other side, tools like Java+Robot or ImageMagick seem to require around 20ms to return the .jpg screenshot, which is pretty slow for the task. But they may be requested right after each time the webcam frame is grabbed and provide the needed synchronization.

  So the sub-questions are :

  1. Does the USD camera's frame rate vary during a single session ?
  2. Are there any tools which provide fast screencasting frame by frame ?
  3. Is there any way to make ffmpeg push a new frame to the .avi file only when program initiates this request ?

  For my task I may either use C++ or Java.

  I am, actually, an interface designer, not the driver programmer, and this task seems to be pretty low-level. I would be grateful for any suggestion and tip !