[IPOL discuss] Video demos: request for comments
Miguel Colom
colom at cmla.ens-cachan.fr
Tue May 1 12:20:28 CEST 2018
Dear all,
The IPOL team is working on adding video data as a native type in
IPOL. It'll allow user to directly upload video files to the demos.
The system will allow two kind of conversion for the videos:
a) The input video will be converted with the HuffYUV codec. This is a
lossless codec which simply uses Huffman compression to reduce the
size of the final file. The algorithm will be provided with one (or
several) video files within an AVI container.
b) For those authors who prefer to handle the video simply as a bunch
of PNG files, we'll provide also this option. For example, if the
users configured that they wanted to read 30 frames from the video,
their problem will find files with the name input0_frame000000.png,
input0_frame000001.png, ... input0_frame000029.png.
The users can choose which option fits best their needs.
In the DDL it'll be possible to specify these options:
- To convert the video to an uncompressed AVI or to a bunch of PNG files
- The maximum number of frames the user wants to process. The system
will read this number of frames reading them from the middle of the
input video.
- Optionally, the maximum size of the frames. The system will zoom-out
the frames if they're bigger that this maximum. Only if this is
specified.
- Optionally, if the video frames should be converted to grayscale.
- The color space (RGB or YUV).
This is still a work in progress, and that's why we're presenting it
here, to know if everybody agrees with this, or if you have any
suggestions or remarks.
About the presentation of the results, the browsers are only capable
to show MPEG4-encoded (.mp4) videos. Unfortunately, MPEG4 videos are
compressed.
While this is not a problem for some applications (say, stabilization,
object detection, color processing), it's not good for enhancement
algorithms such as denoising.
We'd recommend to present the results as a MPEG4 video when the
presence of compression artifacts are not a problem for the
application, but to show individual frames in a gallery otherwise.
We'll provide a script that you can call easily from your demoExtras
scripts to produce videos that you can view on the browsers, as well
as at least one example demo that you can copy from as a stencil to
create others.
Best,
Miguel
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