Video cut

DPF/transforms/video_ffmpeg_transforms.py

@@ -34,17 +34,27 @@ def __init__(
         resizer: Optional[Resizer] = None,
         fps: Optional[int] = None,
         fps_eps: float = 0.1,
+        cut_start_col: Optional[str] = None,
+        cut_duration_col: Optional[str] = None,
+        copy_stream: bool = False,
+        preset: Optional[str] = None,
+        crf: Optional[int] = None,
+        copy_audio_stream: bool = True,
         pool_type: PoolOptions = 'threads',
         workers: int = 16,
         pbar: bool = True,
-        preset: Optional[str] = None,
-        crf: Optional[int] = None,
-        copy_audio_stream: bool = True
     ):
         super().__init__(pool_type, workers, pbar)
         self.resizer = resizer
         self.fps = fps
         self.fps_eps = fps_eps
+        self.cut_start_col = cut_start_col
+        self.cut_duration_col = cut_duration_col
+        if self.cut_duration_col or self.cut_start_col:
+            assert self.cut_duration_col and self.cut_start_col, f"Both {self.cut_duration_col} and {self.cut_start_col} must be specified"
+        self.copy_when_cut = copy_stream
+        if self.copy_when_cut:
+            assert self.copy_when_cut and not (self.fps or self.resizer), "Copy stream can be used only for cutting videos"
 
         self.preset = preset
         self.crf = crf
@@ -53,7 +63,7 @@ def __init__(
         self.default_args = ' '.join(self.get_default_ffmpeg_args())
 
         assert is_ffmpeg_installed(), "Install ffmpeg first"
-        assert self.resizer or self.fps, "At least one transform should be specified"
+        assert self.resizer or self.fps or self.cut_start_col, "At least one transform should be specified"
 
     def get_default_ffmpeg_args(self) -> list[str]:
         args = []
@@ -72,6 +82,8 @@ def required_metadata(self) -> list[str]:
             meta += ['width', 'height']
         if self.fps:
             meta += ['fps']
+        if self.cut_duration_col and self.cut_start_col:
+            meta += [self.cut_start_col, self.cut_duration_col]
         return meta
 
     @property
@@ -90,6 +102,7 @@ def modality(self) -> str:
     def _process_filepath(self, data: TransformsFileData) -> TransformsFileData:
         filepath = data.filepath
         ext = filepath.split('.')[-1]
+        ffmpeg_args_start: list[str] = []
         ffmpeg_args_map: dict[str, list[str]] = {}
         result_metadata: dict[str, Any] = {}
 
@@ -110,10 +123,20 @@ def _process_filepath(self, data: TransformsFileData) -> TransformsFileData:
                 video_fps = float(self.fps)
             result_metadata['fps'] = video_fps
 
+        if self.cut_start_col and self.cut_duration_col and data.metadata[self.cut_start_col] is not None:
+            start = data.metadata[self.cut_start_col]
+            cut_duration = data.metadata[self.cut_duration_col]
+            ffmpeg_args_start.append(f'-ss {start}')
+            ffmpeg_args_map['-t'] = [str(cut_duration)]
+            if self.copy_when_cut:
+                ffmpeg_args_map['-c'] = ['copy']
+                ffmpeg_args_map['-avoid_negative_ts'] = ['1']
+
         if len(ffmpeg_args_map) > 0:
             args_str = convert_ffmpeg_args_to_str(ffmpeg_args_map)
+            args_start_str = ' '.join(ffmpeg_args_start)
             temp_filename = str(uuid.uuid4()) + '.' + ext
-            ffmpeg_command = f'ffmpeg -hide_banner -i {filepath} {args_str} {self.default_args} {temp_filename} -y'
+            ffmpeg_command = f'ffmpeg -hide_banner {args_start_str} -i {filepath} {args_str} {self.default_args} {temp_filename} -y'
             subprocess.run(ffmpeg_command, shell=True, capture_output=True, check=True)
             shutil.move(temp_filename, filepath)
 

docs/transforms.md

@@ -38,4 +38,19 @@ transforms = VideoFFMPEGTransforms(
     workers=8
 )
 processor.apply_transform(transforms)
+```
+
+Fast video cutting:
+_cut_start_ and _cut_duration_ columns should have values in seconds. 
+For example, cutting video from 7 to 11 second should be specified in dataframe as: _cut_start_ = 7, _cut_duration_ = 4
+```python
+from DPF.transforms import VideoFFMPEGTransforms
+
+transforms = VideoFFMPEGTransforms(
+    cut_start_col='cut_start',
+    cut_duration_col='cut_duration',
+    copy_stream=True,
+    workers=4,
+)
+processor.apply_transform(transforms)
 ```