Thumbnail Track: Sprite Sheet
A 6x2 sprite sheet of 160x90 scrub-preview thumbnails in a single JPEG. Players fetch one image rather than 12 separate requests, then crop each tile with a media fragment, which is why the WebVTT index in this group is the load-bearing half of the pair. Useless on its own; that is the point of shipping them together.
Specifications
- Grid
- 6x2
- Tile Size
- 160x90
- Tiles
- 12
- Sheet Size
- 960x180
- Format
- JPEG q82
- Indexed By
- thumbnails.vtt in this group
- Alt Text
- A 6x2 sprite sheet of 160x90 scrub-preview thumbnails in a single JPEG
- Alt Text Source
- description
Testing contract
Expected to pass- Scenario
- Load the sprite sheet and crop the tile addressed by any cue in the companion WebVTT file.
- Expected result
- A 960x180 JPEG (quality 82) holding 12 tiles in a 6x2 grid, each 160x90. Every crop must land exactly on a tile boundary: 6x2 at 160x90 accounts for the full 960x180 with no padding, so an off-by-one in the x/y arithmetic shows up as a visible sliver of the neighbouring tile rather than as an error.
What is a .jpg file?
JPG is the common extension for JPEG, a lossy raster format that uses discrete cosine transform compression tuned for photographic images. It is 8-bit truecolor with no alpha channel, and quality is traded against file size via a compression factor. It is ubiquitous for photos on the web and from cameras.
How to use this file
Use an example JPG to test decoders, EXIF/metadata parsers, re-encoding quality, and orientation handling, or to confirm converters and image pipelines process baseline and progressive scans correctly.
How to use this file for testing
“Thumbnail Track: Sprite Sheet” is a deterministic Testaroo fixture for Streaming manifests, Video QA. HLS playlists and DASH MPDs covering multi-bitrate ladders, byte-range addressing, and segment templates. Served inline with permissive CORS under /files/stream/, so a player can load them from any origin without re-hosting.
Documented properties for this file: JPEG q82. Compare results against paired or grouped companions on this page when present (clean↔damaged, searchable↔scanned, or format twins) so scores stay reproducible across runs.
Download the file once, keep the path stable in CI or local scripts, and treat the spec table as the contract: dimensions, seeds, field lists, and roles are intentional. Corrupt or invalid samples are labelled as such, expect parsers to fail loudly rather than silently accept them.
Media fixtures are short and synthetic by design. Prefer waveform or transcript ground truth in the same group when measuring ASR, trim, upscale, or sync tools; do not assume broadcast-quality masters.
Code examples
<img src="sprite.jpg" alt="Example image" width="640" loading="lazy">Generated by generation/video_streaming_wave.py. Free for any use, no attribution required, license.
Related files
- m4sDASH VOD: Init Segment (init-stream0.m4s)A DASH initialisation segment carrying codec configuration for one representation. Named by the manifest's $RepresentationID$ template, so this file also exercises whether a client resolves template variables correctly rather than pattern-matching filenames.
- m4sDASH VOD: Init Segment (init-stream1.m4s)A DASH initialisation segment carrying codec configuration for one representation. Named by the manifest's $RepresentationID$ template, so this file also exercises whether a client resolves template variables correctly rather than pattern-matching filenames.
- m4sDASH VOD: Init Segment (init-stream2.m4s)A DASH initialisation segment carrying codec configuration for one representation. Named by the manifest's $RepresentationID$ template, so this file also exercises whether a client resolves template variables correctly rather than pattern-matching filenames.
- mpdDASH VOD: Manifest (Playable Package)A complete, playable MPEG-DASH manifest for the same 320x180 at 300 kbps, 480x270 at 700 kbps, 640x360 at 1400 kbps ladder as the HLS package, produced from the same encoder run, so the two can be compared directly as packaging rather than as content. Every segment it references exists in this group. Served inline as application/dash+xml with permissive CORS, so dash.js can load it cross-origin.
- m4sDASH VOD: Media Segment (chunk-stream0-00001.m4s)A one-second DASH media segment, addressed by the manifest's $Number$ template. The same underlying CMAF structure as the HLS segments in the sibling package, which is the whole point of CMAF, and something a fixture set should let you verify rather than take on trust.
- m4sDASH VOD: Media Segment (chunk-stream0-00002.m4s)A one-second DASH media segment, addressed by the manifest's $Number$ template. The same underlying CMAF structure as the HLS segments in the sibling package, which is the whole point of CMAF, and something a fixture set should let you verify rather than take on trust.
