VPF
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65 lines
2.7 KiB
65 lines
2.7 KiB
2 years ago
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import math
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import PyNvCodec as nvc
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import numpy as np
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from towhee.types import VideoFrame
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class VPFDecode:
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def __init__(self, video_path: str, gpu_id: int, start_time: int = None, time_step=None):
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self._gpu_id = gpu_id
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self._nv_dec = nvc.PyNvDecoder(video_path, gpu_id)
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self._start_time = start_time
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self._time_step = time_step
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self._target_w, self._target_h, self._time_base = self._nv_dec.Width(), self._nv_dec.Height(), self._nv_dec.Timebase()
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self._avg_rate = self._nv_dec.AvgFramerate()
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self._to_rgb = nvc.PySurfaceConverter(
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self._target_w, self._target_h, nvc.PixelFormat.NV12, nvc.PixelFormat.RGB, self._gpu_id
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)
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self._cc = nvc.ColorspaceConversionContext(nvc.ColorSpace.BT_709, nvc.ColorRange.JPEG)
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self._pdata = nvc.PacketData()
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def timestamp(self, pts) -> int:
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return int(round(pts * self._time_base * 1000))
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def surface_to_videoframe(self, nv12_surface):
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if nv12_surface.Empty():
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return None
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nv_dwn = nvc.PySurfaceDownloader(self._target_w, self._target_h, nvc.PixelFormat.RGB, self._gpu_id)
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rgb24_small = self._to_rgb.Execute(nv12_surface, self._cc)
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if rgb24_small.Empty():
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raise RuntimeError('Convert to rgb failed')
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rawFrameRGB = np.ndarray(shape=(self._target_h, self._target_w, 3), dtype=np.uint8)
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if not nv_dwn.DownloadSingleSurface(rgb24_small, rawFrameRGB):
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raise RuntimeError('Download image from gpu failed')
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return VideoFrame(rawFrameRGB, 'RGB', self.timestamp(self._pdata.pts), self._pdata.key)
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def time_step_decode(self):
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ts = self._start_time if self._start_time is not None and self._start_time > 0 else 0
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while True:
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seek_ctx = nvc.SeekContext(
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ts, nvc.SeekMode.PREV_KEY_FRAME, nvc.SeekCriteria.BY_TIMESTAMP
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)
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nv12_surface = self._nv_dec.DecodeSingleSurface(seek_ctx, self._pdata)
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frame = self.surface_to_videoframe(nv12_surface)
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if frame is None:
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break
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yield frame
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ts += self._time_step
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def decode(self):
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if self._start_time is not None and self._start_time > 0:
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seek_ctx = nvc.SeekContext(
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self._start_time, nvc.SeekMode.PREV_KEY_FRAME, nvc.SeekCriteria.BY_TIMESTAMP
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)
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nv12_surface = self._nv_dec.DecodeSingleSurface(seek_ctx, self._pdata)
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yield self.surface_to_videoframe(nv12_surface)
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while True:
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nv12_surface = self._nv_dec.DecodeSingleSurface(self._pdata)
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frame = self.surface_to_videoframe(nv12_surface)
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if frame is None:
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break
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yield frame
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