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Add support for NotchLC via ffmpeg #200

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Add support for NotchLC via ffmpeg #200

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fec6a2c
Add NotchLC decoder support
dev-joss Jul 11, 2026
57ee1fc
Give NotchLC its own decoder-setup case
dev-joss Jul 11, 2026
cb18a66
NotchLC: relabel yuva444p12le output as gbrap12le so frames render
dev-joss Jul 11, 2026
f833741
NotchLC: fix colour by tagging BT.709 matrix instead of relabeling to…
dev-joss Jul 12, 2026
41347f4
NotchLC: Move NotchLC case into YUV section and set params for consi…
dev-joss Jul 12, 2026
73c215a
NotchLC: Add comment about incorrect colorspace
dev-joss Jul 12, 2026
0ffc79b
NotchLC: Put frame colorspace fixup behing codec gate instead of pix…
dev-joss Jul 12, 2026
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6 changes: 6 additions & 0 deletions videodecoder/Info.plist
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Original file line number Diff line number Diff line change
Expand Up @@ -111,6 +111,12 @@
<key>CodecType</key>
<string>AFLC</string>
</dict>
<dict>
<key>CodecName</key>
<string>NotchLC</string>
<key>CodecType</key>
<string>nclc</string>
</dict>
<dict>
<key>CodecName</key>
<string>Indeo 2</string>
Expand Down
17 changes: 15 additions & 2 deletions videodecoder/videodecoder.swift
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Expand Up @@ -42,6 +42,7 @@ class VideoDecoder: NSObject, MEVideoDecoder {
0x4458_4433: AV_CODEC_ID_DXV, // 'DXD3'
0x666C_6963: AV_CODEC_ID_FLIC, // 'flic'
0x4146_4C43: AV_CODEC_ID_FLIC, // 'AFLC'
0x6e63_6c63: AV_CODEC_ID_NOTCHLC, // 'nclc'
0x5254_3231: AV_CODEC_ID_INDEO2, // 'RT21'
0x4956_3331: AV_CODEC_ID_INDEO3, // 'IV31'
0x4956_3332: AV_CODEC_ID_INDEO3, // 'IV32'
Expand Down Expand Up @@ -227,6 +228,14 @@ class VideoDecoder: NSObject, MEVideoDecoder {
}
}
}
case AV_CODEC_ID_NOTCHLC:
// NotchLC codec overwrites these with the same values in decode_init, but for consistency with
// other cases we set them here.
params.pointee.format = AV_PIX_FMT_YUVA444P.rawValue;
params.pointee.color_range = AVCOL_RANGE_JPEG
params.pointee.color_space = AVCOL_SPC_RGB // Note, should be BT709 but ffmpeg mislabels...
break

default:
// Shouldn't get here
logger.error(
Expand Down Expand Up @@ -445,7 +454,7 @@ class VideoDecoder: NSObject, MEVideoDecoder {
}

// Fix up color info on the decoded frame
VideoDecoder.fixupColors(frame: frame!)
fixupColors(frame: frame!)

var pixelBuffer: CVPixelBuffer
do {
Expand Down Expand Up @@ -522,10 +531,14 @@ class VideoDecoder: NSObject, MEVideoDecoder {

// Infer color info from the decoded frame. Make educated guesses for unspecified values.
// Mutates the frame's color_primaries, color_trc and colorspace fields in place.
class func fixupColors(frame: UnsafeMutablePointer<AVFrame>) {
func fixupColors(frame: UnsafeMutablePointer<AVFrame>) {

// RGB space. Set color info in case we somehow end up on the zscale path.
if frame.pointee.colorspace == AVCOL_SPC_RGB {
// FFmpeg decoder mislabels notchlc as RGB.
if self.dec_ctx?.pointee.codec_id == AV_CODEC_ID_NOTCHLC {
frame.pointee.colorspace = AVCOL_SPC_BT709
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}
frame.pointee.color_range = AVCOL_RANGE_JPEG
frame.pointee.color_primaries = AVCOL_PRI_BT709
frame.pointee.color_trc = AVCOL_TRC_IEC61966_2_1
Expand Down