From: Steinar H. Gunderson <sgunderson@bigfoot.com>
Date: Tue, 4 Dec 2018 22:15:05 +0000 (+0100)
Subject: Set a FFmpeg-private JPEG marker to signal some Y'CbCr information.
X-Git-Tag: 1.8.0~55
X-Git-Url: https://git.sesse.net/?p=nageru;a=commitdiff_plain;h=012f5333c8958ed3da410ef53493c347028b44c4

Set a FFmpeg-private JPEG marker to signal some Y'CbCr information.
---

diff --git a/futatabi/video_stream.cpp b/futatabi/video_stream.cpp
index 8f11714..6fb8c5c 100644
--- a/futatabi/video_stream.cpp
+++ b/futatabi/video_stream.cpp
@@ -107,6 +107,10 @@ vector<uint8_t> encode_jpeg(const uint8_t *y_data, const uint8_t *cb_data, const
 	cinfo.CCIR601_sampling = true;  // Seems to be mostly ignored by libjpeg, though.
 	jpeg_start_compress(&cinfo, true);
 
+	// This comment marker is private to FFmpeg. It signals limited Y'CbCr range
+	// (and nothing else).
+	jpeg_write_marker(&cinfo, JPEG_COM, (const JOCTET *)"CS=ITU601", strlen("CS=ITU601"));
+
 	JSAMPROW yptr[8], cbptr[8], crptr[8];
 	JSAMPARRAY data[3] = { yptr, cbptr, crptr };
 	for (unsigned y = 0; y < height; y += 8) {
diff --git a/nageru/mjpeg_encoder.cpp b/nageru/mjpeg_encoder.cpp
index 3587d78..614cb5c 100644
--- a/nageru/mjpeg_encoder.cpp
+++ b/nageru/mjpeg_encoder.cpp
@@ -389,6 +389,10 @@ void MJPEGEncoder::init_jpeg_422(unsigned width, unsigned height, VectorDestinat
 	cinfo->comp_info[2].v_samp_factor = 1;
 	cinfo->CCIR601_sampling = true;  // Seems to be mostly ignored by libjpeg, though.
 	jpeg_start_compress(cinfo, true);
+
+	// This comment marker is private to FFmpeg. It signals limited Y'CbCr range
+	// (and nothing else).
+	jpeg_write_marker(cinfo, JPEG_COM, (const JOCTET *)"CS=ITU601", strlen("CS=ITU601"));
 }
 
 vector<uint8_t> MJPEGEncoder::get_jpeg_header(unsigned width, unsigned height, jpeg_compress_struct *cinfo)