From: Steinar H. Gunderson <sgunderson@bigfoot.com>
Date: Tue, 4 Dec 2018 23:41:21 +0000 (+0100)
Subject: Switch to Matroska for Futatabi's output video stream, as it is much better at preser... 
X-Git-Tag: 1.8.0~53
X-Git-Url: https://git.sesse.net/?p=nageru;a=commitdiff_plain;h=1832a337468b13b513d3e77c32cca6207764bd23

Switch to Matroska for Futatabi's output video stream, as it is much better at preserving Y'CbCr details.
---

diff --git a/futatabi/video_stream.cpp b/futatabi/video_stream.cpp
index 6fb8c5c..1957d84 100644
--- a/futatabi/video_stream.cpp
+++ b/futatabi/video_stream.cpp
@@ -238,7 +238,12 @@ VideoStream::~VideoStream() {}
 void VideoStream::start()
 {
 	AVFormatContext *avctx = avformat_alloc_context();
-	avctx->oformat = av_guess_format("nut", nullptr, nullptr);
+
+	// We use Matroska, because it's pretty much the only mux where FFmpeg
+	// allows writing chroma location to override JFIF's default center placement.
+	// (Note that at the time of writing, however, FFmpeg does not correctly
+	// _read_ this information!)
+	avctx->oformat = av_guess_format("matroska", nullptr, nullptr);
 
 	uint8_t *buf = (uint8_t *)av_malloc(MUX_BUFFER_SIZE);
 	avctx->pb = avio_alloc_context(buf, MUX_BUFFER_SIZE, 1, this, nullptr, nullptr, nullptr);