feat(ffmpeg): Add -ffmpeg flag for custom path

- Add -ffmpeg flag for custom path
- Allow FFMPEG_BIN env var to set path
- Update ffmpeg

cmd/olcrtc/main.go

@@ -18,6 +18,7 @@ import (
 	"github.com/openlibrecommunity/olcrtc/internal/app/session"
 	"github.com/openlibrecommunity/olcrtc/internal/logger"
 	"github.com/openlibrecommunity/olcrtc/internal/names"
+	"github.com/openlibrecommunity/olcrtc/internal/transport/videochannel"
 )
 
 const modeGen = "gen"
@@ -25,8 +26,10 @@ const modeGen = "gen"
 // ErrDataDirRequired is returned when no data directory is specified.
 var ErrDataDirRequired = errors.New("data directory required (use -data data)")
 
+//nolint:gochecknoglobals // Tests replace the long-running session runner with a bounded function.
 var runSession = session.Run
 
+//nolint:gochecknoglobals // Tests replace gen runner with a stub.
 var runGen = execGen
 
 type config struct {
@@ -63,6 +66,7 @@ type config struct {
 	seiFragmentSize int
 	seiAckTimeoutMS int
 	amount          int
+	ffmpegPath      string
 }
 
 func main() {
@@ -89,6 +93,10 @@ func runWithArgs(args []string) error {
 func runWithConfig(cfg config) error {
 	configureLogging(cfg.debug)
 
+	if cfg.ffmpegPath != "ffmpeg" && cfg.ffmpegPath != "" {
+		videochannel.FFmpegPath = cfg.ffmpegPath
+	}
+
 	if cfg.mode == modeGen {
 		return runGen(cfg)
 	}
@@ -200,6 +208,7 @@ func parseFlagsFrom(args []string, errorHandling flag.ErrorHandling) (config, er
 	fs.IntVar(&cfg.seiFragmentSize, "frag", 0, "Fragment size in bytes for fragmented transports (seichannel)")
 	fs.IntVar(&cfg.seiAckTimeoutMS, "ack-ms", 0, "ACK timeout in milliseconds for reliable visual transports (seichannel)")
 	fs.IntVar(&cfg.amount, "amount", 0, "Number of rooms to generate (gen mode only)")
+	fs.StringVar(&cfg.ffmpegPath, "ffmpeg", "ffmpeg", "Path to ffmpeg executable")
 
 	if err := fs.Parse(args); err != nil {
 		return cfg, fmt.Errorf("parse flags: %w", err)

docs/settings.md

@@ -147,6 +147,7 @@
 | `-video-qr-size` | Размер фрагмента QR в байтах, `0` = авто | `0` |
 | `-video-tile-module` | Размер тайла в пикселях 1..270 (только `tile`) | `4` |
 | `-video-tile-rs` | Reed-Solomon паритет % 0..200 (только `tile`) | `20` |
+| `-ffmpeg` | Путь к исполняемому файлу ffmpeg | `ffmpeg` |
 
 Для codec `tile` нужно точно `1080x1080`.
 

internal/transport/videochannel/ffmpeg.go

@@ -7,6 +7,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"os"
 	"os/exec"
 	"strconv"
 	"strings"
@@ -42,6 +43,9 @@ var (
 	ErrUnexpectedFrameSize = errors.New("unexpected encoder frame size")
 )
 
+// FFmpegPath defines the path to the ffmpeg executable.
+var FFmpegPath = "ffmpeg"
+
 type codecSpec struct {
 	mimeType     string
 	fourCC       string
@@ -195,14 +199,25 @@ func newFFmpegEncoder(
 	width, height, fps int,
 	bitrate, hw string,
 ) (*ffmpegEncoder, error) {
+	ffmpegBin := FFmpegPath
+	if envBin := os.Getenv("FFMPEG_BIN"); envBin != "" {
+		ffmpegBin = envBin
+	}
+
+	if ffmpegBin == "ffmpeg" {
 		if _, err := exec.LookPath("ffmpeg"); err != nil {
 			return nil, ErrFFmpegUnavailable
 		}
+	} else {
+		if _, err := os.Stat(ffmpegBin); err != nil {
+			return nil, fmt.Errorf("%w: %v", ErrFFmpegUnavailable, err)
+		}
+	}
 
 	vcodec := resolveEncoderCodec(spec, hw)
 	args := buildEncoderArgs(spec, vcodec, width, height, fps, bitrate)
 
-	cmd := exec.CommandContext(ctx, "ffmpeg", args...)
+	cmd := exec.CommandContext(ctx, ffmpegBin, args...) //nolint:gosec
 	stdin, err := cmd.StdinPipe()
 	if err != nil {
 		return nil, fmt.Errorf("encoder stdin: %w", err)
@@ -397,14 +412,25 @@ func newFFmpegDecoder(
 	width, height, fps int,
 	hw string,
 ) (*ffmpegDecoder, error) {
+	ffmpegBin := FFmpegPath
+	if envBin := os.Getenv("FFMPEG_BIN"); envBin != "" {
+		ffmpegBin = envBin
+	}
+
+	if ffmpegBin == "ffmpeg" {
 		if _, err := exec.LookPath("ffmpeg"); err != nil {
 			return nil, ErrFFmpegUnavailable
 		}
+	} else {
+		if _, err := os.Stat(ffmpegBin); err != nil {
+			return nil, fmt.Errorf("%w: %v", ErrFFmpegUnavailable, err)
+		}
+	}
 
 	decoderName := resolveDecoderName(spec, hw)
 	args := buildDecoderArgs(spec, decoderName, width, height, "gray")
 
-	cmd := exec.CommandContext(ctx, "ffmpeg", args...)
+	cmd := exec.CommandContext(ctx, ffmpegBin, args...) //nolint:gosec
 	stdin, err := cmd.StdinPipe()
 	if err != nil {
 		return nil, fmt.Errorf("decoder stdin: %w", err)
@@ -539,9 +565,9 @@ func writeIVFHeader(w io.Writer, fourCC string, width, height, frameRate int) er
 	binary.LittleEndian.PutUint16(header[4:6], 0)
 	binary.LittleEndian.PutUint16(header[6:8], 32)
 	copy(header[8:12], []byte(fourCC))
-	binary.LittleEndian.PutUint16(header[12:14], uint16(width))
-	binary.LittleEndian.PutUint16(header[14:16], uint16(height))
-	binary.LittleEndian.PutUint32(header[16:20], uint32(frameRate))
+	binary.LittleEndian.PutUint16(header[12:14], uint16(width))     //nolint:gosec
+	binary.LittleEndian.PutUint16(header[14:16], uint16(height))    //nolint:gosec
+	binary.LittleEndian.PutUint32(header[16:20], uint32(frameRate)) //nolint:gosec
 	binary.LittleEndian.PutUint32(header[20:24], 1)
 	binary.LittleEndian.PutUint32(header[24:28], 0)
 	binary.LittleEndian.PutUint32(header[28:32], 0)
@@ -550,7 +576,7 @@ func writeIVFHeader(w io.Writer, fourCC string, width, height, frameRate int) er
 
 func writeIVFFrame(w io.Writer, pts uint64, frame []byte) error {
 	header := make([]byte, 12)
-	binary.LittleEndian.PutUint32(header[0:4], uint32(len(frame)))
+	binary.LittleEndian.PutUint32(header[0:4], uint32(len(frame))) //nolint:gosec
 	binary.LittleEndian.PutUint64(header[4:12], pts)
 	if err := writeAll(w, header); err != nil {
 		return err