Heavily compressed clips with a high-quality reference

Colourisation Input — colour-patches, 50% Desaturated

The colour-patches plate with 50% of its saturation removed, leaving 50% of the original chroma. This is the faded-archive case rather than the black-and-white one: some colour information survives, so the task is restoration rather than invention, and a model that ignores the residual chroma is throwing away the strongest signal it has.

File: MP4 · Colour · 640x360
Use case: Video colourisationCompression artefacts+1· Conversion set

Colourisation Input — colour-patches, 80% Desaturated

The colour-patches plate with 80% of its saturation removed, leaving 19% of the original chroma. This is the faded-archive case rather than the black-and-white one: some colour information survives, so the task is restoration rather than invention, and a model that ignores the residual chroma is throwing away the strongest signal it has.

File: MP4 · Colour · 640x360
Use case: Video colourisationCompression artefacts+1· Conversion set

Colourisation Input — pan-city, 50% Desaturated

The pan-city plate with 50% of its saturation removed, leaving 50% of the original chroma. This is the faded-archive case rather than the black-and-white one: some colour information survives, so the task is restoration rather than invention, and a model that ignores the residual chroma is throwing away the strongest signal it has.

File: MP4 · Colour · 640x360
Use case: Video colourisationCompression artefacts+1· Conversion set

Colourisation Input — pan-city, 80% Desaturated

The pan-city plate with 80% of its saturation removed, leaving 19% of the original chroma. This is the faded-archive case rather than the black-and-white one: some colour information survives, so the task is restoration rather than invention, and a model that ignores the residual chroma is throwing away the strongest signal it has.

File: MP4 · Colour · 640x360
Use case: Video colourisationCompression artefacts+1· Conversion set

Colourisation Input — gradient-sky, 50% Desaturated

The gradient-sky plate with 50% of its saturation removed, leaving 50% of the original chroma. This is the faded-archive case rather than the black-and-white one: some colour information survives, so the task is restoration rather than invention, and a model that ignores the residual chroma is throwing away the strongest signal it has.

File: MP4 · Colour · 640x360
Use case: Video colourisationCompression artefacts+1· Conversion set

Colourisation Input — gradient-sky, 80% Desaturated

The gradient-sky plate with 80% of its saturation removed, leaving 19% of the original chroma. This is the faded-archive case rather than the black-and-white one: some colour information survives, so the task is restoration rather than invention, and a model that ignores the residual chroma is throwing away the strongest signal it has.

File: MP4 · Colour · 640x360
Use case: Video colourisationCompression artefacts+1· Conversion set

Compression Reference — gradient-sky at CRF 14

The high-quality reference for the gradient-sky compression ladder, at CRF 14. Each clip in this group is the SAME source frames encoded at a progressively higher quantiser, so the only variable is the encoder setting. Useful both for artefact-removal models and for calibrating a quality metric against settings whose visual cost is already known.

File: MP4 · Compress · 640x360
Use case: Compression artefactsVideo codecs+1· Conversion set

Compression Input — gradient-sky at CRF 28

The gradient-sky plate at CRF 28 — mild artefacts. Encoded from the original frames rather than transcoded from the reference, so it carries exactly one generation of loss and the comparison is clean. On this plate the damage shows as banding across the smooth gradient, which is the artefact viewers notice first and metrics score most poorly.

File: MP4 · Compress · 640x360
Use case: Compression artefactsVideo codecs+1· Conversion set

Compression Input — gradient-sky at CRF 36

The gradient-sky plate at CRF 36 — clearly visible artefacts. Encoded from the original frames rather than transcoded from the reference, so it carries exactly one generation of loss and the comparison is clean. On this plate the damage shows as banding across the smooth gradient, which is the artefact viewers notice first and metrics score most poorly.

File: MP4 · Compress · 640x360
Use case: Compression artefactsVideo codecs+1· Conversion set

Compression Input — gradient-sky at CRF 44

The gradient-sky plate at CRF 44 — severe artefacts. Encoded from the original frames rather than transcoded from the reference, so it carries exactly one generation of loss and the comparison is clean. On this plate the damage shows as banding across the smooth gradient, which is the artefact viewers notice first and metrics score most poorly.

File: MP4 · Compress · 640x360
Use case: Compression artefactsVideo codecs+1· Conversion set

Compression Input — gradient-sky at CRF 51

The gradient-sky plate at CRF 51 — extreme — the codec's limit artefacts. Encoded from the original frames rather than transcoded from the reference, so it carries exactly one generation of loss and the comparison is clean. On this plate the damage shows as banding across the smooth gradient, which is the artefact viewers notice first and metrics score most poorly.

File: MP4 · Compress · 640x360
Use case: Compression artefactsVideo codecs+1· Conversion set

Compression Reference — text-motion at CRF 14

The high-quality reference for the text-motion compression ladder, at CRF 14. Each clip in this group is the SAME source frames encoded at a progressively higher quantiser, so the only variable is the encoder setting. Useful both for artefact-removal models and for calibrating a quality metric against settings whose visual cost is already known.

File: MP4 · Compress · 640x360
Use case: Compression artefactsVideo codecs+1· Conversion set

Compression Input — text-motion at CRF 28

The text-motion plate at CRF 28 — mild artefacts. Encoded from the original frames rather than transcoded from the reference, so it carries exactly one generation of loss and the comparison is clean. On this plate the damage shows as ringing around glyph edges, where legibility gives a pass/fail signal that needs no metric.

File: MP4 · Compress · 640x360
Use case: Compression artefactsVideo codecs+1· Conversion set

Compression Input — text-motion at CRF 36

The text-motion plate at CRF 36 — clearly visible artefacts. Encoded from the original frames rather than transcoded from the reference, so it carries exactly one generation of loss and the comparison is clean. On this plate the damage shows as ringing around glyph edges, where legibility gives a pass/fail signal that needs no metric.

File: MP4 · Compress · 640x360
Use case: Compression artefactsVideo codecs+1· Conversion set

Compression Input — text-motion at CRF 44

The text-motion plate at CRF 44 — severe artefacts. Encoded from the original frames rather than transcoded from the reference, so it carries exactly one generation of loss and the comparison is clean. On this plate the damage shows as ringing around glyph edges, where legibility gives a pass/fail signal that needs no metric.

File: MP4 · Compress · 640x360
Use case: Compression artefactsVideo codecs+1· Conversion set

Compression Input — text-motion at CRF 51

The text-motion plate at CRF 51 — extreme — the codec's limit artefacts. Encoded from the original frames rather than transcoded from the reference, so it carries exactly one generation of loss and the comparison is clean. On this plate the damage shows as ringing around glyph edges, where legibility gives a pass/fail signal that needs no metric.

File: MP4 · Compress · 640x360
Use case: Compression artefactsVideo codecs+1· Conversion set

Compression Reference — detail-chart at CRF 14

The high-quality reference for the detail-chart compression ladder, at CRF 14. Each clip in this group is the SAME source frames encoded at a progressively higher quantiser, so the only variable is the encoder setting. Useful both for artefact-removal models and for calibrating a quality metric against settings whose visual cost is already known.

File: MP4 · Compress · 640x360
Use case: Compression artefactsVideo codecs+1· Conversion set

Compression Input — detail-chart at CRF 28

The detail-chart plate at CRF 28 — mild artefacts. Encoded from the original frames rather than transcoded from the reference, so it carries exactly one generation of loss and the comparison is clean. On this plate the fine wedges collapse first, showing exactly which spatial frequencies the quantiser discarded.

File: MP4 · Compress · 640x360
Use case: Compression artefactsVideo codecs+1· Conversion set

Compression Input — detail-chart at CRF 36

The detail-chart plate at CRF 36 — clearly visible artefacts. Encoded from the original frames rather than transcoded from the reference, so it carries exactly one generation of loss and the comparison is clean. On this plate the fine wedges collapse first, showing exactly which spatial frequencies the quantiser discarded.

File: MP4 · Compress · 640x360
Use case: Compression artefactsVideo codecs+1· Conversion set

Compression Input — detail-chart at CRF 44

The detail-chart plate at CRF 44 — severe artefacts. Encoded from the original frames rather than transcoded from the reference, so it carries exactly one generation of loss and the comparison is clean. On this plate the fine wedges collapse first, showing exactly which spatial frequencies the quantiser discarded.

File: MP4 · Compress · 640x360
Use case: Compression artefactsVideo codecs+1· Conversion set

Compression Input — detail-chart at CRF 51

The detail-chart plate at CRF 51 — extreme — the codec's limit artefacts. Encoded from the original frames rather than transcoded from the reference, so it carries exactly one generation of loss and the comparison is clean. On this plate the fine wedges collapse first, showing exactly which spatial frequencies the quantiser discarded.

File: MP4 · Compress · 640x360
Use case: Compression artefactsVideo codecs+1· Conversion set

Colour Signalling — BT.709 (HD SDR)

The HD standard, and what a player assumes when a file says nothing. The reference member of this group: every other clip carries identical pixels and different signalling. Every clip in this group carries the SAME picture and differs only in its colour signalling, so any difference in how a player renders them is entirely a metadata-handling difference.

File: MKV · Hdr · 640x360
Use case: Video codecsCompression artefacts+1· Conversion set

Colour Signalling — BT.601 (SD)

The standard-definition matrix. Decoding BT.601 content as BT.709 (or the reverse) shifts every colour subtly — greens and reds most visibly. It is the single most common colour bug in transcode pipelines, and this pair reproduces it on demand. Every clip in this group carries the SAME picture and differs only in its colour signalling, so any difference in how a player renders them is entirely a metadata-handling difference.

File: MKV · Hdr · 640x360
Use case: Video codecsCompression artefacts+1· Conversion set

Colour Signalling — BT.2020 SDR (Wide Gamut)

Wide-gamut primaries with a conventional SDR transfer — wide colour without HDR. Frequently mishandled because tooling assumes BT.2020 always implies PQ or HLG. Every clip in this group carries the SAME picture and differs only in its colour signalling, so any difference in how a player renders them is entirely a metadata-handling difference.

File: MKV · Hdr · 640x360
Use case: Video codecsCompression artefacts+1· Conversion set

Colour Signalling — HDR10 (PQ, BT.2020, 10-bit)

HDR10 signalling: BT.2020 primaries with the SMPTE ST 2084 perceptual quantiser, 10-bit. Be clear about what this fixture is — the picture is ordinary SDR content TAGGED as HDR, so it is a test of metadata handling and tone-mapping paths, not a reference for HDR image quality. A player that ignores the transfer function will render it washed out and far too dark, which is precisely the failure worth reproducing. Every clip in this group carries the SAME picture and differs only in its colour signalling, so any difference in how a player renders them is entirely a metadata-handling difference.

File: MKV · Hdr · 640x360
Use case: Video codecsCompression artefacts+1· Conversion set

Colour Signalling — HLG (Hybrid Log-Gamma)

Hybrid Log-Gamma, the broadcast HDR transfer designed to stay watchable on an SDR display. As with the HDR10 fixture, the picture itself is SDR content carrying HLG signalling, so this tests transfer-function detection and the SDR fallback path rather than HDR rendering. Every clip in this group carries the SAME picture and differs only in its colour signalling, so any difference in how a player renders them is entirely a metadata-handling difference.

File: MKV · Hdr · 640x360
Use case: Video codecsCompression artefacts+1· Conversion set