117 lines
3.2 KiB
Python
117 lines
3.2 KiB
Python
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import cython
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import cython.cimports.libav as lib
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from cython.cimports.av.error import err_check
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from cython.cimports.av.packet import Packet
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from cython.cimports.av.stream import Stream
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from cython.cimports.libc.errno import EAGAIN
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@cython.final
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@cython.cclass
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class BitStreamFilterContext:
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"""
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Initializes a bitstream filter: a way to directly modify packet data.
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Wraps :ffmpeg:`AVBSFContext`
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:param Stream in_stream: A stream that defines the input codec for the bitfilter.
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:param Stream out_stream: A stream whose codec is overwritten using the output parameters from the bitfilter.
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"""
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def __cinit__(
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self,
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filter_description,
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in_stream: Stream | None = None,
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out_stream: Stream | None = None,
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):
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res: cython.int
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filter_str: cython.p_char = filter_description
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with cython.nogil:
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res = lib.av_bsf_list_parse_str(filter_str, cython.address(self.ptr))
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err_check(res)
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if in_stream is not None:
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with cython.nogil:
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res = lib.avcodec_parameters_copy(
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self.ptr.par_in, in_stream.ptr.codecpar
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)
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err_check(res)
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with cython.nogil:
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res = lib.av_bsf_init(self.ptr)
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err_check(res)
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if out_stream is not None:
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with cython.nogil:
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res = lib.avcodec_parameters_copy(
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out_stream.ptr.codecpar, self.ptr.par_out
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)
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err_check(res)
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lib.avcodec_parameters_to_context(
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out_stream.codec_context.ptr, out_stream.ptr.codecpar
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)
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def __dealloc__(self):
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if self.ptr:
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lib.av_bsf_free(cython.address(self.ptr))
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@cython.ccall
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def filter(self, packet: Packet | None = None):
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"""
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Processes a packet based on the filter_description set during initialization.
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Multiple packets may be created.
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:type: list[Packet]
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"""
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res: cython.int
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new_packet: Packet
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with cython.nogil:
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res = lib.av_bsf_send_packet(
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self.ptr, packet.ptr if packet is not None else cython.NULL
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)
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err_check(res)
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output: list = []
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while True:
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new_packet = Packet()
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with cython.nogil:
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res = lib.av_bsf_receive_packet(self.ptr, new_packet.ptr)
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if res == -EAGAIN or res == lib.AVERROR_EOF:
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return output
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err_check(res)
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if res:
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return output
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output.append(new_packet)
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@cython.ccall
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def flush(self):
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"""
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Reset the internal state of the filter.
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Should be called e.g. when seeking.
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Can be used to make the filter usable again after draining it with EOF marker packet.
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"""
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lib.av_bsf_flush(self.ptr)
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@cython.cfunc
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def get_filter_names() -> set:
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names: set = set()
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ptr: cython.pointer[cython.const[lib.AVBitStreamFilter]]
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opaque: cython.p_void = cython.NULL
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while True:
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ptr = lib.av_bsf_iterate(cython.address(opaque))
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if ptr:
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names.add(ptr.name)
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else:
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break
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return names
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bitstream_filters_available = get_filter_names()
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