| import cython |
| import cython.cimports.libav as lib |
| from cython.cimports.av.codec.codec import Codec |
| from cython.cimports.av.error import err_check |
| from cython.cimports.av.packet import Packet |
| from cython.cimports.av.stream import Stream |
| from cython.cimports.libc.errno import EAGAIN |
|
|
|
|
| @cython.final |
| @cython.cclass |
| class BitStreamFilterContext: |
| """ |
| Initializes a bitstream filter: a way to directly modify packet data. |
| |
| Wraps :ffmpeg:`AVBSFContext` |
| |
| :param in_stream: Defines the input codec for the bitfilter. A :class:`.Stream` |
| copies the full input codec parameters, while a :class:`.Codec` or a codec-name |
| ``str`` only pins the input codec, which is all a codec-specific filter (such as |
| ``h264_mp4toannexb``) needs to initialize. |
| :type in_stream: :class:`.Stream`, :class:`.Codec`, str, or None |
| :param Stream out_stream: A stream whose codec is overwritten using the output parameters from the bitfilter. |
| """ |
|
|
| def __cinit__( |
| self, |
| filter_description, |
| in_stream: Stream | Codec | str | None = None, |
| out_stream: Stream | None = None, |
| ): |
| res: cython.int |
| filter_str: cython.p_char = filter_description |
|
|
| with cython.nogil: |
| res = lib.av_bsf_list_parse_str(filter_str, cython.address(self.ptr)) |
| err_check(res) |
|
|
| if isinstance(in_stream, Stream): |
| with cython.nogil: |
| res = lib.avcodec_parameters_copy( |
| self.ptr.par_in, cython.cast(Stream, in_stream).ptr.codecpar |
| ) |
| err_check(res) |
| elif in_stream is not None: |
| |
| |
| codec: Codec = ( |
| in_stream if isinstance(in_stream, Codec) else Codec(in_stream) |
| ) |
| self.ptr.par_in.codec_id = codec.ptr.id |
| self.ptr.par_in.codec_type = codec.ptr.type |
|
|
| with cython.nogil: |
| res = lib.av_bsf_init(self.ptr) |
| err_check(res) |
|
|
| if out_stream is not None: |
| with cython.nogil: |
| res = lib.avcodec_parameters_copy( |
| out_stream.ptr.codecpar, self.ptr.par_out |
| ) |
| err_check(res) |
| |
| |
| if out_stream.codec_context is not None: |
| lib.avcodec_parameters_to_context( |
| out_stream.codec_context.ptr, out_stream.ptr.codecpar |
| ) |
|
|
| def __dealloc__(self): |
| if self.ptr: |
| lib.av_bsf_free(cython.address(self.ptr)) |
|
|
| @cython.ccall |
| def filter(self, packet: Packet | None = None): |
| """ |
| Processes a packet based on the filter_description set during initialization. |
| Multiple packets may be created. |
| |
| :type: list[Packet] |
| """ |
| res: cython.int |
| new_packet: Packet |
|
|
| with cython.nogil: |
| res = lib.av_bsf_send_packet( |
| self.ptr, packet.ptr if packet is not None else cython.NULL |
| ) |
| err_check(res) |
|
|
| output: list = [] |
| while True: |
| new_packet = Packet() |
| with cython.nogil: |
| res = lib.av_bsf_receive_packet(self.ptr, new_packet.ptr) |
|
|
| if res == -EAGAIN or res == lib.AVERROR_EOF: |
| return output |
|
|
| err_check(res) |
| if res: |
| return output |
|
|
| output.append(new_packet) |
|
|
| @cython.ccall |
| def flush(self): |
| """ |
| Reset the internal state of the filter. |
| Should be called e.g. when seeking. |
| Can be used to make the filter usable again after draining it with EOF marker packet. |
| """ |
| lib.av_bsf_flush(self.ptr) |
|
|
|
|
| @cython.cfunc |
| def get_filter_names() -> set: |
| names: set = set() |
| ptr: cython.pointer[cython.const[lib.AVBitStreamFilter]] |
| opaque: cython.p_void = cython.NULL |
| while True: |
| ptr = lib.av_bsf_iterate(cython.address(opaque)) |
| if ptr: |
| names.add(ptr.name) |
| else: |
| break |
|
|
| return names |
|
|
|
|
| bitstream_filters_available = get_filter_names() |
|
|
