122 lines
3.9 KiB
Python
122 lines
3.9 KiB
Python
"""FFmpeg command builder for Deltacast SDI recording."""
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from datetime import datetime
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from backend.app.config import Settings
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from backend.app.models import RecorderConfig, CodecType
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class FFmpegCommandBuilder:
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"""Builds FFmpeg commands for Deltacast SDI recording."""
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def __init__(self, settings: Settings):
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self.settings = settings
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def build_command(self, config: RecorderConfig) -> list[str]:
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"""Build complete FFmpeg command for recording a port.
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Args:
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config: RecorderConfig with port, codec, and output settings
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Returns:
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List of command arguments ready for subprocess execution
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"""
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command = [self.settings.ffmpeg_path]
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# Add input device arguments
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command.extend(self._get_input_args(config.port_index))
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# Add codec arguments
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command.extend(self._get_codec_args(config))
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# Add output file arguments
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command.extend(self._get_output_args(config))
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# Add SRT streaming if enabled
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if config.srt_enabled:
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command.extend(self._get_srt_output_args(config))
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return command
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def _get_input_args(self, port_index: int) -> list[str]:
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"""Get Deltacast input device args for the given port.
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Args:
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port_index: Port index (0-based)
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Returns:
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FFmpeg input arguments: ["-f", "deltacast", "-i", "deltacast://N"]
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"""
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return [
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"-f", "deltacast",
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"-i", f"deltacast://{port_index}"
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]
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def _get_codec_args(self, config: RecorderConfig) -> list[str]:
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"""Map CodecType to FFmpeg codec arguments.
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Args:
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config: RecorderConfig with codec selection
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Returns:
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Codec-specific FFmpeg arguments
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"""
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args = []
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if config.codec == CodecType.PRORES:
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args.extend(["-c:v", "prores_ks"])
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# Map quality profiles to prores_ks profile levels
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profile_map = {
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"hq": "3", # High quality
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"mq": "2", # Medium quality
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"lq": "0", # Low quality
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}
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profile = profile_map.get(config.quality_profile, "3")
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args.extend(["-profile:v", profile])
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elif config.codec == CodecType.DNXHD:
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args.extend(["-c:v", "dnxhd"])
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# Use bitrate from config, default to 185M if not set
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bitrate = f"{config.bitrate}M" if config.bitrate else "185M"
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args.extend(["-b:v", bitrate])
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elif config.codec == CodecType.UNCOMPRESSED:
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args.extend(["-c:v", "rawvideo", "-pix_fmt", "uyvy422"])
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elif config.codec == CodecType.H264:
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args.extend(["-c:v", "libx264"])
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# Use bitrate from config, default to 50M if not set
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bitrate = f"{config.bitrate}M" if config.bitrate else "50M"
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args.extend(["-b:v", bitrate])
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return args
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def _get_output_args(self, config: RecorderConfig) -> list[str]:
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"""Get output file arguments including format and path.
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Args:
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config: RecorderConfig with output path
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Returns:
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Output format and file path arguments
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"""
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# Substitute {timestamp} with current datetime in format YYYYMMDD_HHMMSS
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output_path = config.recording_path
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if "{timestamp}" in output_path:
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timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
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output_path = output_path.replace("{timestamp}", timestamp)
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return ["-f", "mxf", output_path]
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def _get_srt_output_args(self, config: RecorderConfig) -> list[str]:
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"""Get SRT streaming output arguments if enabled.
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Args:
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config: RecorderConfig with SRT settings
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Returns:
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SRT output arguments or empty list if SRT disabled
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"""
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if not config.srt_enabled or not config.srt_destination:
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return []
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return ["-f", "mpegts", config.srt_destination]
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