|
| 1 | +from pathlib import Path |
| 2 | +from typing import Union |
| 3 | + |
| 4 | +import torch |
| 5 | +from torch import Tensor |
| 6 | + |
| 7 | +from torchcodec import _core |
| 8 | + |
| 9 | + |
| 10 | +class VideoEncoder: |
| 11 | + """A video encoder. |
| 12 | +
|
| 13 | + Args: |
| 14 | + frames (``torch.Tensor``): The frames to encode. This must be a 4D |
| 15 | + tensor of shape ``(N, C, H, W)`` where N is the number of frames, |
| 16 | + C is 3 channels (RGB), H is height, and W is width. |
| 17 | + A 3D tensor of shape ``(C, H, W)`` is also accepted as a single RGB frame. |
| 18 | + Values must be uint8 in the range ``[0, 255]``. |
| 19 | + frame_rate (int): The frame rate to use when encoding the |
| 20 | + **input** ``frames``. |
| 21 | + """ |
| 22 | + |
| 23 | + def __init__(self, frames: Tensor, *, frame_rate: int): |
| 24 | + torch._C._log_api_usage_once("torchcodec.encoders.VideoEncoder") |
| 25 | + if not isinstance(frames, Tensor): |
| 26 | + raise ValueError(f"Expected frames to be a Tensor, got {type(frames) = }.") |
| 27 | + if frames.ndim == 3: |
| 28 | + # make it 4D and assume single RGB frame, CHW -> NCHW |
| 29 | + frames = torch.unsqueeze(frames, 0) |
| 30 | + if frames.ndim != 4: |
| 31 | + raise ValueError(f"Expected 3D or 4D frames, got {frames.shape = }.") |
| 32 | + if frames.dtype != torch.uint8: |
| 33 | + raise ValueError(f"Expected uint8 frames, got {frames.dtype = }.") |
| 34 | + if frame_rate <= 0: |
| 35 | + raise ValueError(f"{frame_rate = } must be > 0.") |
| 36 | + |
| 37 | + self._frames = frames |
| 38 | + self._frame_rate = frame_rate |
| 39 | + |
| 40 | + def to_file( |
| 41 | + self, |
| 42 | + dest: Union[str, Path], |
| 43 | + ) -> None: |
| 44 | + """Encode frames into a file. |
| 45 | +
|
| 46 | + Args: |
| 47 | + dest (str or ``pathlib.Path``): The path to the output file, e.g. |
| 48 | + ``video.mp4``. The extension of the file determines the video |
| 49 | + format and container. |
| 50 | + """ |
| 51 | + _core.encode_video_to_file( |
| 52 | + frames=self._frames, |
| 53 | + frame_rate=self._frame_rate, |
| 54 | + filename=str(dest), |
| 55 | + ) |
| 56 | + |
| 57 | + def to_tensor( |
| 58 | + self, |
| 59 | + format: str, |
| 60 | + ) -> Tensor: |
| 61 | + """Encode frames into raw bytes, as a 1D uint8 Tensor. |
| 62 | +
|
| 63 | + Args: |
| 64 | + format (str): The format of the encoded frames, e.g. "mp4", "mov", |
| 65 | + "mkv", "avi", "webm", "flv", or "gif" |
| 66 | +
|
| 67 | + Returns: |
| 68 | + Tensor: The raw encoded bytes as 4D uint8 Tensor. |
| 69 | + """ |
| 70 | + return _core.encode_video_to_tensor( |
| 71 | + frames=self._frames, |
| 72 | + frame_rate=self._frame_rate, |
| 73 | + format=format, |
| 74 | + ) |
| 75 | + |
| 76 | + def to_file_like( |
| 77 | + self, |
| 78 | + file_like, |
| 79 | + format: str, |
| 80 | + ) -> None: |
| 81 | + """Encode frames into a file-like object. |
| 82 | +
|
| 83 | + Args: |
| 84 | + file_like: A file-like object that supports ``write()`` and |
| 85 | + ``seek()`` methods, such as io.BytesIO(), an open file in binary |
| 86 | + write mode, etc. Methods must have the following signature: |
| 87 | + ``write(data: bytes) -> int`` and ``seek(offset: int, whence: |
| 88 | + int = 0) -> int``. |
| 89 | + format (str): The format of the encoded frames, e.g. "mp4", "mov", |
| 90 | + "mkv", "avi", "webm", "flv", or "gif". |
| 91 | + """ |
| 92 | + _core.encode_video_to_file_like( |
| 93 | + frames=self._frames, |
| 94 | + frame_rate=self._frame_rate, |
| 95 | + format=format, |
| 96 | + file_like=file_like, |
| 97 | + ) |
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