FAQs - Technical

Where can I see a list of the main characteristics of each clip set?

The Products Summary page has a table at the bottom of the page which lists the main characteristics (resolution, clip length, clip type, bit depth, format etc.).  Also available are extracts of each user manual (the first 25-30 pages), which gives full information on each clip set.

Can I see some examples?

There is a show reel which gives a shortened version of some of the clips; also available are 6 example images from each clip set (single frames at full resolution).

What format were the clips filmed in?

Unless otherwise stated, all clips were filmed 1920x1080 progressive with various professional cameras.

What about the audio?

In almost all cases, audio was recorded at the time the video was filmed.  This audio is provided, matched to the video, in both MPEG1 LII and PCM formats.  Although not bought for the audio, when was the last time you had video without audio?  In which case, why would you buy or use test video without audio - how can you check if sync is lost during encoding if there is no synchronized audio?

What sizes/resolutions are available?

The video is available in most sizes, from mobile to web through SD NTSC and PAL, to 720p, 1080i, 1080p and 2K & 4K D-Cinema.  See the Summary page for a list of sizes/resolutions (the table showing the details of each clip set is at the bottom of the page).

What if I want a different formats/sizes for the video?

Most of the clip sets are standard sizes, e.g. HD or SD or D-Cinema.  With the T2V004 LowRes clip set and T2V005 HighRes clip set are provided software utility programs that allow the video to be down-sized to intermediate / non-standard sizes - of virtually any size required.

However, we are always keen to hear what clips you want to have: please send a request to .

What bit-depths & chroma sub-sampling is available?  Can I get 10-bit, 12-bit or 14-bit, 4:2:2 or 4:4:4 ?

The clips in the T2V005 HighRes set are 4:2:2 and 4:4:4 at 10, 12 and 14-bits per sample. (And up to 4K D-Cinema resolution.)  The other clip sets are 8-bits per sample, 4:2:0 (mostly HD although SD and lower resolutions also in the T2V004 LowRes clip set.

I need video at 24 / 29.97 / 30 / 50 / 59.94 / 60 frames per second

Although many Tvids were filmed at 25 frames per second, the clips are uncompressed so can be played back at whatever speed required.  In fact, playing back at 24fps gives a virtually imperceptible difference; playing back at 29.97 or 30fps is noticeable but is acceptable visually and in many of the sequences will not be noticeable.

However, some clip sets have been filmed at 30 (29.97), or 50, or 60 (59.94) frames per second, and other clip sets have been produced with 30 (29.97) or 60 (59.94) frames per second video [50fps sets are in production], such as T2V016 Synth3060: please see the summary list for details of frame rates in each clip set (at bottom of page).

Is any software supplied?

With each test set, a utility programs may be supplied depending if it is appropriate with the clip set concerned.  More information is provided on these in each user manual (and is covered within the user manual extracts which are viewable).  The utility programs currently comprise:

• yuvmake1088 (and yuvmake1088hr): add extra lines at the top/bottom of a 1920x1080 YUV file to make it 1920x1088
• yuvcropsize (and yuvcropsizehr): reduce size of video by removing lines from the top and/or columns from the right of each video frame: allows virtually any reduced size video to be made from the video files provided
• yuvletterbox: add black bars top & bottom (or left & right) on the supplied video sequences, to make letterboxed (or pillarboxed) video
• yuvfieldcombine: combine interlaced fields which are stored in alternating format (bottom field followed by top field, each half-height) into frames where alternate lines contain alternate fields

How are they supplied, on what media?

All Tvids are supplied on USB 2.0 hard drive.  Depending upon the size of hard drive, it may be mains powered or USB line powered.  If mains powered an appropriate mains power cord will be supplied for your country.

More information on the FAQs - Hardware page.

How can I view or play the video when I get it (it’s all in YUV)?  What about playing in real-time on SDI / ASI / DVI / HDMI ?

To play the YUV files directly on a computer, there are quite a few YUV viewers available - please see the YUV viewers page for a list.

Playing the YUV out on an SDI / ASI / DVI / HDMI link, specific I/O hardware is required for the SDI / ASI / DVI / HDMI interface.  In addition, fast disks and computer are required to transfer the YUV video from the files on disk to the I/O in real-time.  A white paper discusses this in detail; there is also information on the Broadcasters application page.

It looks like there is a logo on the bottom left of each frame - why?

As Tvids are uncompressed video, rights management/control is not possible other than by our license agreement. Adding a logo helps remind all that the clips are licensed.  Adding a logo is not very unrealistic as any programs have logo bugs of some sort.  The logo is meant to be small enough as not to be intrusive and is added in such a way that it is designed not to interfere with the encoding process, as it is static and aligns with macroblock boundaries, so that after being encoded in an I-frame there will be minimal data used for the logo in subsequent P and B frames.

What post-processing has been done on the clips?

In general, nothing.  Where re-sizing has been done (e.g. to go from 1080p to 720p) then this has been done using our custom algorithms.  Sometimes clips have been added together with fades etc.: at this point some post-processing / a re-encode has been done, as required.  (And in this regard, Tvids are identical to ‘normal’ video.)

What test coverage do Tvids offer?

How well does your encoder cope with grainy night-time video?  Or video where there is lots of fast movement / scene changes?  Or water, or moire patterns, or perhaps monochrome blue sky? Or will your encoder have a problem where video goes rapidly in and out of focus?  Or where there is lots of text, or very bright colours, or low contrast, or many areas that look very similar - will your encoder pick the right ones to track the motion of? Tvids allows you to instantly have a comprehensive test set for your encoder - so you know it will cope with anything, efficiently and robustly.  (And the PDF documentation allows you to quickly find particular clips which have features that are 'difficult' for your encoder.)

Typically each set comprises a range of subjects, motion, colours, light levels designed to test and stress video encoders by providing a varied set of conditions:

• subject types such as people, traffic, buildings, sky, water, trees, text..
• movement types such as panning, zooming in/out, tracking, hand-held camera
• subject motion such as into, out of or across the picture, in front of and partially behind objects
• lighting conditions, from bright sunlight, dull daylight, shaded areas, indoors..
• varying camera properties such as depth of field, in/out-of-focus..
• hard to encode items such as reflections, fine lines, patterns, round objects..
• and with sound associated with some clips

In many cases the video is harder to encode than might normally be expected, as the lighting conditions are not ideal or there is significant camera movement, or the focus varies.  These features are deliberately used as they often cause the most difficulty to video encoders and represent the worst case that the encoder should encounter in 'normal / real' use.