Tag Archives: 720p

Making of Omashay’s “Wish You Looked at Me” music video

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Last month I edited the Wish You Looked at Me video clip for the Omashay project. This is a side-project of Cool Cavemen’s saxophonist. The video is finally available on YouTube:

All the video material was shot by Tomasito itself, with his Canon PowerShot SX200IS point-and-shoot camera. This camera produce 30fps 720p clips.

He came to me with all these .mov files, and the idea of combining them into a classical split-screen layout. He had no idea how to do this, so I accepted to help him with my technical knowledge.

I fired up my Kdenlive (v0.8 on Kubuntu 11.04) and in a matter of hours, the project was done. With source videos of 720p, I naturally chose 1080p as the final resolution. I kept the 30fps framerate to not alter the original time resolution.

The most boring part of the edit was the first step, in which we synced all clips together with the reference audio track. Here is how the timeline looked, with one track for each instrument:

We had to work around some annoying Kdenlive bugs, as it had some problems handling so much tracks in parallel. Fortunately these bugs were fixed in a matter of days with a new build of MLT.

Next step was to mark out the structure of the song. Tomasito placed blue markers along the timeline, and we cut all tracks following that structure. It resulted in a matrix of clips:

Then for each segment, we choose the 4 clips that we wanted to show and deleted the others:

Then I created 4 special tracks to which I applied a global positioning and scaling effect, to have each track fill one corner of the screen. We moved there all the clips we selected in the previous step, and cleaned up the timeline a bit:

At this stage the project was mostly done. It was just a matter of adding intro, outro and fade in/out to obtain our final video:

Tomasito basically did the whole editing of the project. And I have some evidences:

I just showed him how to manipulate Kdenlive timelines, and cut/move/paste clips, and he was absolutely autonomous in a matter of minutes. I just did the transitions, the title cards integration and the screen splitting. I’m not sure I deserve the title of editor for this project, but he still insisted to add me in the credits… :)

Of course split-screen is far from new and was done a million times before. But it’s a simple yet effective concept that require absolutely no investment (apart time). This also gave me the opportunity to play again with Kdenlive and assess its user-friendliness and edit capabilities on a real project. But at the end, it was just a great excuse to work with a friend on a little video project ! :)

Canon EOS 7D Movie Samples

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Here is a collection of Eiffel Tower’s videos I took today with my Canon EOS 7D. These quick and dirty clips were shots this late afternoon.

Please don’t look at the image quality. That’s not the point. We’re interested in bitstream, video/audio codecs and media container here.

These files are as they came out of the camera and can serve as references. The idea is to provide raw data access to developpers and hackers to let them add or enhance 7D’s support to their software.

Here are seven 10 seconds video clips, corresponding to the 7 video modes offered by the 7D (that’s a lot of 7′s):

ResolutionFramerateShutter Speed
1920×1080 (1080p)23.976 fps (24 fps)1/50
1920×1080 (1080p)25 fps1/50
1920×1080 (1080p)29.97 fps (30 fps)1/60
1280×720 (720p)50 fps1/100
1280×720 (720p)59.94 fps (60 fps)1/125
640×480 (480p)50 fps1/100
640×480 (480p)59.94 fps (60 fps)1/125

Again, these files were extracted right out of the camera, without any modification.

Even if these details have no importance, here are some parameters under which these clips were shots (may be useful for debugging):

  • Lens: Canon EF-S 15-85 mm f/3,5-5,6 IS USM
  • IS: On
  • ISO: 100
  • Exposition compensation: 0
  • White balance: Daylight
  • Picture style: Standard
  • Auto Lighting Optimizer: Disabled
  • Highlight Tone Priority: Disabled
  • Peripheral illumintion correction: Off
  • Audio format: PCM, 48kHz, 16 bits
  • Camera firmware: 1.2.1

Cool Cavemen live at Gayant Expo, part II.

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Here is “Funky Cops”, the second Cool Cavemen’s live song at Gayant Expo:

I released this video two weeks ago for Cool Cavemen. As I try to release one video every week, I give a high priority to the editing work. This leaves me with little time to write on this blog.

But starting from now, I plan to publish a blog post for each video. I’ll use these articles to write about one aspect of the work involved behind the scene.

In the first post of the series, I gave you the context in which the concert was performed. Today the post is dedicated to video formats. First, let’s talk about the video sources…

The concert was shot with 4 cameras. Among them, only two were of the same kinds. Those were part of the live broadcasting system of the event. This explain the “mise en abyme” effect in the background screen:

At the end of the gig, I wasn’t be able to retrieve two continuous feeds. Instead I got an already-edited video corresponding to what was projected live (*sigh*).

As a result, I ended with 3 video sources:

  1. A DVD-like video stream (576i) produced by my consumer-grade camera (now for sale at 0.01€ on ebay). It produces 720×576 pixels interlaced frames at 25 fps, with a pixel ratio of 16:15 (giving 768×576 pixels frames at 1:1) and a final display ratio of 4:3. All encoded as a 9 Mbps MPEG-2 stream in a MPEG-PS container.
  2. A 720p video stream: 1280×720 pixels progressive frames at 30 fps, with 1:1 pixel ratio and 16:9 display ratio, encoded as variable bitrate MJPEG stream in a QuickTime container.
  3. The already-edited video stream (Half-D1) from unidentified Sony cameras: 352×576 pixels interlaced frames at 25 fps, with a pixel ratio of 24:11 (giving 768×576 pixels frames at 1:1) and a final display ratio of 4:3. The file was a 6 Mbps MPEG-2 stream in a MPEG-PS container.

All those informations were extracted thanks to ffmeg, mplayer and tcprobe (see all the command lines involved).

As you can see, this is an absolute mess ! There is no consistency ! And now, before starting the video editing itself, I have this important decision to make: choose the final video format, in which my project will be rendered.

Let me explain how I did it. But before, I have to tell you something. To me, an interlaced video at 25 fps is just a 50 fps stream with half the vertical resolution. This is important for you to know if you want to understand how I perceive quality. I’ll probably explain it in details in a future article. But for now, this should give you enough insights on how I came up with my two strategies.

The first one is the “maximizing” strategy. It consists of keeping the best parts from all video sources. Based on formats described above, this means 1280×720 pixels progressive frames at 50 fps, with 1:1 pixel ratio and 16:9 display ratio. In this process we create non-existent informations by scaling and interpolating spatial and temporal data.

The second strategy is the “minimizing” strategy which, you can guess from its name, is the exact opposite of the first one. Here we discard spatial and temporal informations until we reach a sub-format shared by all sources. In our example, this gives 352×288 pixels frames at 30 fps, with a pixel ratio of 24:22 and a display ratio of 4:3. There, 288 is half 576, which is the result of using a deinterlacing “bob” filter on video streams #1 and #3 to get 50 fps. And for the pixel ratio, as we “bobbed” the interlaced videos, we keep the worst horizontal scaling and multiply the vertical scaling by two, which give us 24:22.

For this project, I finally went by the first stategy. I choosed to render the project to a 720p video at 25 fps, with a 1:1 pixel ratio and 16:9 display ratio. Also known as… HD-Ready !

Why this format ? It’s the most popular one that closely match the characteristics we established three paragraphs above. It’s also quite standard, and “gives a chance” to the second video source to display in full resolution. I also felt that it will cause less pain when confronted to the wide range of software video players out there.

Now that I have decided which format to use, I can create a project in my video editor with the right parameters and start the editing process. But this is another topic for another post !