viser_ffmpeg/
path.rs

1use std::env;
2use std::path::PathBuf;
3use std::process::Command;
4
5/// Returns the path to the ffmpeg binary.
6///
7/// Resolution order:
8/// 1. `VISER_FFMPEG` environment variable
9/// 2. `bin/ffmpeg/ffmpeg` relative to the working directory
10/// 3. `"ffmpeg"` (system PATH)
11pub fn ffmpeg_path() -> String {
12    if let Ok(p) = env::var("VISER_FFMPEG")
13        && !p.is_empty()
14    {
15        return p;
16    }
17    if let Some(p) = local_binary("ffmpeg") {
18        return p;
19    }
20    "ffmpeg".into()
21}
22
23/// Returns the path to the ffprobe binary.
24///
25/// Resolution order:
26/// 1. `VISER_FFPROBE` environment variable
27/// 2. `bin/ffmpeg/ffprobe` relative to the working directory
28/// 3. `"ffprobe"` (system PATH)
29pub fn ffprobe_path() -> String {
30    if let Ok(p) = env::var("VISER_FFPROBE")
31        && !p.is_empty()
32    {
33        return p;
34    }
35    if let Some(p) = local_binary("ffprobe") {
36        return p;
37    }
38    "ffprobe".into()
39}
40
41/// Minimum FFmpeg version required (major).
42const MIN_FFMPEG_MAJOR: u32 = 6;
43
44/// Parsed FFmpeg version.
45#[derive(Debug, Clone)]
46pub struct FfmpegVersion {
47    /// Path to the binary that reported this version.
48    pub binary: String,
49    /// Major version number.
50    pub major: u32,
51    /// Minor version number.
52    pub minor: u32,
53    /// Raw version string as parsed from the binary's output.
54    pub raw: String,
55}
56
57/// Run `ffmpeg -version` and parse the version line. Returns an error if the
58/// binary is not found or the version is too old.
59pub fn check_ffmpeg() -> anyhow::Result<FfmpegVersion> {
60    let path = ffmpeg_path();
61    let output = Command::new(&path)
62        .arg("-version")
63        .output()
64        .map_err(|e| anyhow::anyhow!("ffmpeg not found at '{path}': {e}"))?;
65    if !output.status.success() {
66        anyhow::bail!("ffmpeg at '{path}' exited with error");
67    }
68    let stdout = String::from_utf8_lossy(&output.stdout);
69    let first_line = stdout.lines().next().unwrap_or("").trim().to_string();
70    let version = parse_ffmpeg_version(&first_line, path)?;
71    if version.major < MIN_FFMPEG_MAJOR {
72        anyhow::bail!(
73            "ffmpeg {}.{} is too old — viser requires FFmpeg >= {MIN_FFMPEG_MAJOR}.0 (found {})",
74            version.major,
75            version.minor,
76            version.raw,
77        );
78    }
79    Ok(version)
80}
81
82/// Run `ffprobe -version` and parse the version line. Returns an error if ffprobe
83/// is not found.
84pub fn check_ffprobe() -> anyhow::Result<FfmpegVersion> {
85    let path = ffprobe_path();
86    let output = Command::new(&path)
87        .arg("-version")
88        .output()
89        .map_err(|e| anyhow::anyhow!("ffprobe not found at '{path}': {e}"))?;
90    if !output.status.success() {
91        anyhow::bail!("ffprobe at '{path}' exited with error");
92    }
93    let stdout = String::from_utf8_lossy(&output.stdout);
94    let first_line = stdout.lines().next().unwrap_or("").trim().to_string();
95    parse_ffmpeg_version(&first_line, path)
96}
97
98fn parse_ffmpeg_version(line: &str, path: String) -> anyhow::Result<FfmpegVersion> {
99    // Typical first line: "ffmpeg version 7.1.1 Copyright ..."
100    // or "ffmpeg version n7.1.1-... Copyright ..."
101    let version_str = line
102        .strip_prefix("ffmpeg version ")
103        .or_else(|| line.strip_prefix("ffprobe version "))
104        .and_then(|s| s.split_whitespace().next())
105        .map(|s| s.trim_start_matches('n'))
106        .ok_or_else(|| anyhow::anyhow!("could not parse version from: {line}"))?;
107    let parts: Vec<&str> = version_str.split('.').collect();
108    let major: u32 = parts
109        .first()
110        .and_then(|s| s.parse().ok())
111        .ok_or_else(|| anyhow::anyhow!("could not parse major version from: {version_str}"))?;
112    let minor: u32 = parts.get(1).and_then(|s| s.parse().ok()).unwrap_or(0);
113    Ok(FfmpegVersion { binary: path, major, minor, raw: version_str.to_string() })
114}
115
116/// Known valid libvmaf model names. Models are resolved by FFmpeg's built-in
117/// libvmaf library; these are the names FFmpeg recognizes.
118const KNOWN_VMAF_MODELS: &[&str] =
119    &["vmaf_v0.6.1", "vmaf_v0.6.1neg", "vmaf_4k_v0.6.1", "vmaf_b_v0.6.3", "vmaf_4k_v0.6.1neg"];
120
121/// Validate that the given VMAF model name is recognized by libvmaf.
122pub fn validate_vmaf_model(model: &str) -> anyhow::Result<()> {
123    if KNOWN_VMAF_MODELS.contains(&model) {
124        return Ok(());
125    }
126    anyhow::bail!("unknown VMAF model '{model}'. Known models: {}", KNOWN_VMAF_MODELS.join(", "));
127}
128
129fn local_binary(name: &str) -> Option<String> {
130    let mut path = PathBuf::from("bin").join("ffmpeg");
131    if cfg!(windows) {
132        path = path.join(format!("{name}.exe"));
133    } else {
134        path = path.join(name);
135    }
136    if path.exists() { Some(path.to_string_lossy().into_owned()) } else { None }
137}
138
139#[cfg(test)]
140mod tests {
141    use super::*;
142
143    // ── VMAF model validation ──
144    #[test]
145    fn test_validate_vmaf_model_known() {
146        assert!(validate_vmaf_model("vmaf_v0.6.1").is_ok());
147        assert!(validate_vmaf_model("vmaf_v0.6.1neg").is_ok());
148        assert!(validate_vmaf_model("vmaf_4k_v0.6.1").is_ok());
149        assert!(validate_vmaf_model("vmaf_b_v0.6.3").is_ok());
150        assert!(validate_vmaf_model("vmaf_4k_v0.6.1neg").is_ok());
151    }
152
153    #[test]
154    fn test_validate_vmaf_model_unknown() {
155        assert!(validate_vmaf_model("vmaf_v99.0").is_err());
156        assert!(validate_vmaf_model("unknown_model").is_err());
157        assert!(validate_vmaf_model("").is_err());
158    }
159
160    // ── Version parsing ──
161    #[test]
162    fn test_parse_ffmpeg_version_standard() {
163        let v = parse_ffmpeg_version("ffmpeg version 7.1.1 Copyright", "ffmpeg".into()).unwrap();
164        assert_eq!(v.major, 7);
165        assert_eq!(v.minor, 1);
166        assert_eq!(v.raw, "7.1.1");
167    }
168
169    #[test]
170    fn test_parse_ffmpeg_version_ffprobe() {
171        let v = parse_ffmpeg_version("ffprobe version 6.0.0 Copyright", "ffprobe".into()).unwrap();
172        assert_eq!(v.major, 6);
173        assert_eq!(v.minor, 0);
174        assert_eq!(v.raw, "6.0.0");
175    }
176
177    #[test]
178    fn test_parse_ffmpeg_version_with_n_prefix() {
179        let v =
180            parse_ffmpeg_version("ffmpeg version n7.1.1-1234 Copyright", "ffmpeg".into()).unwrap();
181        assert_eq!(v.major, 7);
182        assert_eq!(v.minor, 1);
183        assert_eq!(v.raw, "7.1.1-1234");
184    }
185
186    #[test]
187    fn test_parse_ffmpeg_version_old() {
188        let v = parse_ffmpeg_version("ffmpeg version 4.4.0 Copyright", "ffmpeg".into()).unwrap();
189        assert_eq!(v.major, 4);
190        assert_eq!(v.minor, 4);
191    }
192
193    #[test]
194    fn test_parse_ffmpeg_version_major_only() {
195        let v = parse_ffmpeg_version("ffmpeg version 7 Copyright", "ffmpeg".into()).unwrap();
196        assert_eq!(v.major, 7);
197        assert_eq!(v.minor, 0);
198    }
199
200    #[test]
201    fn test_parse_ffmpeg_version_two_parts() {
202        let v = parse_ffmpeg_version("ffmpeg version 7.0 Copyright", "ffmpeg".into()).unwrap();
203        assert_eq!(v.major, 7);
204        assert_eq!(v.minor, 0);
205    }
206
207    #[test]
208    fn test_parse_ffmpeg_version_three_parts() {
209        let v = parse_ffmpeg_version("ffmpeg version 5.1.3 Copyright", "ffmpeg".into()).unwrap();
210        assert_eq!(v.major, 5);
211        assert_eq!(v.minor, 1);
212    }
213
214    #[test]
215    fn test_parse_ffmpeg_version_unrecognized_line() {
216        assert!(parse_ffmpeg_version("some random text", "ffmpeg".into()).is_err());
217    }
218
219    #[test]
220    fn test_parse_ffmpeg_version_empty() {
221        assert!(parse_ffmpeg_version("", "ffmpeg".into()).is_err());
222    }
223
224    #[test]
225    fn test_parse_ffmpeg_version_bogus_after_prefix() {
226        // "ffmpeg version abc" — "abc" is not a valid version
227        assert!(parse_ffmpeg_version("ffmpeg version not-a-version", "ffmpeg".into()).is_err());
228    }
229
230    // ── Path functions ──
231    #[test]
232    fn test_ffmpeg_path_returns_string() {
233        let path = ffmpeg_path();
234        assert!(!path.is_empty());
235    }
236
237    #[test]
238    fn test_ffprobe_path_returns_string() {
239        let path = ffprobe_path();
240        assert!(!path.is_empty());
241    }
242
243    #[test]
244    fn test_ffmpeg_path_respects_env() {
245        let old = std::env::var("VISER_FFMPEG").ok();
246        unsafe {
247            std::env::set_var("VISER_FFMPEG", "/custom/ffmpeg");
248        }
249        assert_eq!(ffmpeg_path(), "/custom/ffmpeg");
250        unsafe {
251            match old {
252                Some(v) => std::env::set_var("VISER_FFMPEG", v),
253                None => std::env::remove_var("VISER_FFMPEG"),
254            }
255        }
256    }
257
258    #[test]
259    fn test_ffprobe_path_respects_env() {
260        let old = std::env::var("VISER_FFPROBE").ok();
261        unsafe {
262            std::env::set_var("VISER_FFPROBE", "/custom/ffprobe");
263        }
264        assert_eq!(ffprobe_path(), "/custom/ffprobe");
265        unsafe {
266            match old {
267                Some(v) => std::env::set_var("VISER_FFPROBE", v),
268                None => std::env::remove_var("VISER_FFPROBE"),
269            }
270        }
271    }
272}
viser_ffmpeg/path.rs

viser_ffmpeg/
path.rs
