Image MIME Reference
HSJ2
JPEG 2000 Image Sequence (Obsolete)
image/hsj2
VS
Tencent TAP Image
image/vnd.tencent.tap
Tencent-TAP
A complete technical comparison of JPEG 2000 Image Sequence (Obsolete) and Tencent TAP Image — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | HSJ2 | Tencent-TAP |
|---|---|---|
| Transparency (Alpha) | Yes | ✕ No |
| Animation Support | Yes | ✕ No |
| Progressive Loading | Yes | ✕ No |
| HDR Support | Yes | ✕ No |
| EXIF Metadata | Yes | ✕ No |
| ICC Color Profile | Yes | ✕ No |
JPEG 2000 Image Sequence (Obsolete)
image/hsj2
Extension
.hsj2
Container
HEIF / ISOBMFF (ISO/IEC 15444-16 Obsolete)
Compression
Lossy / Lossless
Algorithm
Motion JPEG 2000 (ISO/IEC 15444-3)
Color Depth
8-bit, 10-bit, 12-bit, 16-bit
Developed by
ISO/IEC JTC 1 / ITU-T
Released
2019
Magic Bytes
XX XX XX XX 66 74 79 70 68 73 6A 32
Tencent TAP Image
image/vnd.tencent.tap
Extension
.tap
Container
Proprietary Tencent Container
Compression
Unknown (Proprietary)
Algorithm
Unknown
Color Depth
Unknown
Developed by
Tencent (Registered by Ni Hui)
Released
2014
Magic Bytes
Unknown (Proprietary)
Browser Support Comparison
| Browser | HSJ2 | Tencent-TAP |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
HSJ2
HSJ2 Strengths
- Historically attempted to combine Motion JPEG 2000 sequences with the flexible metadata capabilities of the HEIF container
- Supported mathematically lossless compression and scalable wavelet decoding
Limitations
- Officially deprecated by the standardization body (ISO/IEC JTC 1)
- Completely superseded by image/hej2k, rendering hsj2 files obsolete for any new development or archiving
- Zero web browser compatibility and negligible modern software support
Tencent-TAP
Tencent-TAP Strengths
- Officially registered with IANA, ensuring a unique MIME type identifier for internal Tencent network routing and content negotiation
Limitations
- Completely undocumented and closed-source, making it impossible to decode or parse outside of Tencent's software
- Shares its file extension (.tap) with numerous other established legacy formats, leading to frequent automated file misidentification by Node/Python libraries
When to choose which format
HSJ2
Use HSJ2 when…
- Legacy Archival
- Deprecated Workflows
Tencent-TAP
Use Tencent-TAP when…
- Internal Tencent Ecosystem Applications
- Proprietary Mobile or Gaming Assets