From a2a8fda91e6c3e5fa39e2f2c9ca6f4f030b04da5 Mon Sep 17 00:00:00 2001
From: Varun Patil <varunpatil@ucla.edu>
Date: Mon, 3 Apr 2023 18:55:26 -0700
Subject: [PATCH] Use copy for H264

---
 stream.go | 36 ++++++++++++++++++++++--------------
 1 file changed, 22 insertions(+), 14 deletions(-)

diff --git a/stream.go b/stream.go
index b568474d..a8339016 100644
--- a/stream.go
+++ b/stream.go
@@ -16,12 +16,13 @@ import (
 )
 
 const (
-	ENCODER_X264 = "libx264"
+	ENCODER_COPY  = "copy"
+	ENCODER_X264  = "libx264"
 	ENCODER_VAAPI = "h264_vaapi"
 	ENCODER_NVENC = "h264_nvenc"
 
 	QUALITY_MAX = "max"
-	CODEC_H264 = "h264"
+	CODEC_H264  = "h264"
 )
 
 type Stream struct {
@@ -363,15 +364,20 @@ func (s *Stream) transcodeArgs(startAt float64) []string {
 	// encoder selection
 	CV := ENCODER_X264
 
-	// Check whether hwaccel should be used
-	if s.c.VAAPI {
-		CV = ENCODER_VAAPI
-		extra := "-hwaccel vaapi -hwaccel_device /dev/dri/renderD128 -hwaccel_output_format vaapi"
-		args = append(args, strings.Split(extra, " ")...)
-	} else if s.c.NVENC {
-		CV = ENCODER_NVENC
-		extra := "-hwaccel cuda"
-		args = append(args, strings.Split(extra, " ")...)
+	if s.m.probe.CodecName == CODEC_H264 && s.quality == QUALITY_MAX {
+		// Use original stream
+		CV = ENCODER_COPY
+	} else {
+		// Check whether hwaccel should be used
+		if s.c.VAAPI {
+			CV = ENCODER_VAAPI
+			extra := "-hwaccel vaapi -hwaccel_device /dev/dri/renderD128 -hwaccel_output_format vaapi"
+			args = append(args, strings.Split(extra, " ")...)
+		} else if s.c.NVENC {
+			CV = ENCODER_NVENC
+			extra := "-hwaccel cuda"
+			args = append(args, strings.Split(extra, " ")...)
+		}
 	}
 
 	// Input specs
@@ -404,8 +410,11 @@ func (s *Stream) transcodeArgs(startAt float64) []string {
 	}
 
 	// Apply filter
-	filter := fmt.Sprintf("%s,%s=%s", format, scaler, strings.Join(scalerArgs, ":"))
-	args = append(args, []string{"-vf", filter}...)
+	if CV != ENCODER_COPY {
+		filter := fmt.Sprintf("%s,%s=%s", format, scaler, strings.Join(scalerArgs, ":"))
+		args = append(args, []string{"-vf", filter}...)
+		args = append(args, []string{"-profile:v", "main"}...)
+	}
 
 	// Apply bitrate cap if not max quality
 	if s.quality != QUALITY_MAX {
@@ -419,7 +428,6 @@ func (s *Stream) transcodeArgs(startAt float64) []string {
 	args = append(args, []string{
 		"-map", "0:v:0",
 		"-c:v", CV,
-		"-profile:v", "main",
 	}...)
 
 	// Device specific output args