From b554c2820ab516f65226540e8bd1fc019823cadf Mon Sep 17 00:00:00 2001
From: Saxon <saxon@ausocean.org>
Date: Sat, 2 Nov 2019 10:31:40 +1030
Subject: [PATCH] revid: wrote implementation of Start method for Raspivid
 implementation

---
 revid/raspivid.go | 76 +++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 71 insertions(+), 5 deletions(-)

diff --git a/revid/raspivid.go b/revid/raspivid.go
index f467b727..27b2c223 100644
--- a/revid/raspivid.go
+++ b/revid/raspivid.go
@@ -27,8 +27,12 @@ package revid
 import (
 	"errors"
 	"fmt"
+	"io"
+	"os/exec"
+	"strings"
 
 	"bitbucket.org/ausocean/av/codec/codecutil"
+	"bitbucket.org/ausocean/utils/logger"
 )
 
 // Raspivid AVDevice configuration defaults.
@@ -47,10 +51,6 @@ const (
 	raspividDefaultFramerate        = 25
 )
 
-type Raspivid struct {
-	c Config
-}
-
 var (
 	errBadCodec            = errors.New("codec bad or unset, defaulting")
 	errBadRotation         = errors.New("rotation bad or unset, defaulting")
@@ -66,6 +66,12 @@ var (
 	errBadQuantization     = errors.New("quantization bad or unset, defaulting")
 )
 
+type Raspivid struct {
+	cfg Config
+	cmd *exec.Cmd
+	out io.ReadCloser
+}
+
 type multiError []error
 
 func (me multiError) Error() string {
@@ -140,6 +146,66 @@ func (r *Raspivid) Set(c Config) error {
 		c.AutoWhiteBalance = raspividDefaultAutoWhiteBalance
 	}
 
-	r.c = c
+	r.cfg = c
 	return multiError(errs)
 }
+
+func (r *Raspivid) Start() error {
+	const disabled = "0"
+	args := []string{
+		"--output", "-",
+		"--nopreview",
+		"--timeout", disabled,
+		"--width", fmt.Sprint(r.cfg.Width),
+		"--height", fmt.Sprint(r.cfg.Height),
+		"--bitrate", fmt.Sprint(r.cfg.Bitrate * 1000), // Convert from kbps to bps.
+		"--framerate", fmt.Sprint(r.cfg.FrameRate),
+		"--rotation", fmt.Sprint(r.cfg.Rotation),
+		"--brightness", fmt.Sprint(r.cfg.Brightness),
+		"--saturation", fmt.Sprint(r.cfg.Saturation),
+		"--exposure", fmt.Sprint(r.cfg.Exposure),
+		"--awb", fmt.Sprint(r.cfg.AutoWhiteBalance),
+	}
+
+	if r.cfg.FlipHorizontal {
+		args = append(args, "--hflip")
+	}
+
+	if r.cfg.FlipVertical {
+		args = append(args, "--vflip")
+	}
+	if r.cfg.FlipHorizontal {
+		args = append(args, "--hflip")
+	}
+
+	switch r.cfg.InputCodec {
+	default:
+		return fmt.Errorf("revid: invalid input codec: %v", r.cfg.InputCodec)
+	case codecutil.H264:
+		args = append(args,
+			"--codec", "H264",
+			"--inline",
+			"--intra", fmt.Sprint(r.cfg.MinFrames),
+		)
+		if r.cfg.VBR {
+			args = append(args, "-qp", fmt.Sprint(r.cfg.Quantization))
+		}
+	case codecutil.MJPEG:
+		args = append(args, "--codec", "MJPEG")
+	}
+	r.cfg.Logger.Log(logger.Info, pkg+"raspivid args", "raspividArgs", strings.Join(args, " "))
+	r.cmd = exec.Command("raspivid", args...)
+
+	var err error
+	r.out, err = r.cmd.StdoutPipe()
+	if err != nil {
+		return fmt.Errorf("could not pipe command output: %w", err)
+	}
+
+	err = r.cmd.Start()
+	if err != nil {
+		return fmt.Errorf("could not start raspivid command: %w", err)
+	}
+
+	return nil
+}