| cimport libav as lib | |
| from libc.errno cimport EAGAIN | |
| from av.error cimport err_check | |
| from av.packet cimport Packet | |
| from av.stream cimport Stream | |
| cdef class BitStreamFilterContext: | |
| """ | |
| Initializes a bitstream filter: a way to directly modify packet data. | |
| Wraps :ffmpeg:`AVBSFContext` | |
| :param Stream in_stream: A stream that defines the input codec for the bitfilter. | |
| :param Stream out_stream: A stream whose codec is overwritten using the output parameters from the bitfilter. | |
| """ | |
| def __cinit__(self, filter_description, Stream in_stream=None, Stream out_stream=None): | |
| cdef int res | |
| cdef char *filter_str = filter_description | |
| with nogil: | |
| res = lib.av_bsf_list_parse_str(filter_str, &self.ptr) | |
| err_check(res) | |
| if in_stream is not None: | |
| with nogil: | |
| res = lib.avcodec_parameters_copy(self.ptr.par_in, in_stream.ptr.codecpar) | |
| err_check(res) | |
| with nogil: | |
| res = lib.av_bsf_init(self.ptr) | |
| err_check(res) | |
| if out_stream is not None: | |
| with nogil: | |
| res = lib.avcodec_parameters_copy(out_stream.ptr.codecpar, self.ptr.par_out) | |
| err_check(res) | |
| lib.avcodec_parameters_to_context(out_stream.codec_context.ptr, out_stream.ptr.codecpar) | |
| def __dealloc__(self): | |
| if self.ptr: | |
| lib.av_bsf_free(&self.ptr) | |
| cpdef filter(self, Packet packet=None): | |
| """ | |
| Processes a packet based on the filter_description set during initialization. | |
| Multiple packets may be created. | |
| :type: list[Packet] | |
| """ | |
| cdef int res | |
| cdef Packet new_packet | |
| with nogil: | |
| res = lib.av_bsf_send_packet(self.ptr, packet.ptr if packet is not None else NULL) | |
| err_check(res) | |
| output = [] | |
| while True: | |
| new_packet = Packet() | |
| with 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) | |
| cpdef 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) | |
| cdef get_filter_names(): | |
| names = set() | |
| cdef const lib.AVBitStreamFilter *ptr | |
| cdef void *opaque = NULL | |
| while True: | |
| ptr = lib.av_bsf_iterate(&opaque) | |
| if ptr: | |
| names.add(ptr.name) | |
| else: | |
| break | |
| return names | |
| bitstream_filters_available = get_filter_names() | |