File size: 4,741 Bytes
9b0e299 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 | import cython
from cython.cimports import libav as lib
from cython.cimports.av.buffer import ByteSource, bytesource
from cython.cimports.av.codec.context import CodecContext
from cython.cimports.av.error import err_check
from cython.cimports.av.packet import Packet
from cython.cimports.av.subtitles.subtitle import SubtitleProxy, SubtitleSet
from cython.cimports.cpython.bytes import PyBytes_FromStringAndSize
from cython.cimports.libc.string import memcpy
@cython.final
@cython.cclass
class SubtitleCodecContext(CodecContext):
@property
def subtitle_header(self) -> bytes | None:
"""Get the subtitle header data (ASS/SSA format for text subtitles)."""
if (
self.ptr.subtitle_header == cython.NULL
or self.ptr.subtitle_header_size <= 0
):
return None
return PyBytes_FromStringAndSize(
cython.cast(cython.p_char, self.ptr.subtitle_header),
self.ptr.subtitle_header_size,
)
@subtitle_header.setter
def subtitle_header(self, data: bytes | None) -> None:
"""Set the subtitle header data."""
source: ByteSource
if data is None:
lib.av_freep(cython.address(self.ptr.subtitle_header))
self.ptr.subtitle_header_size = 0
else:
source = bytesource(data)
self.ptr.subtitle_header = cython.cast(
cython.p_uchar,
lib.av_realloc(
self.ptr.subtitle_header,
source.length + lib.AV_INPUT_BUFFER_PADDING_SIZE,
),
)
if not self.ptr.subtitle_header:
raise MemoryError("Cannot allocate subtitle_header")
memcpy(self.ptr.subtitle_header, source.ptr, source.length)
self.ptr.subtitle_header_size = cython.cast(cython.int, source.length)
self.subtitle_header_set = True
def __dealloc__(self) -> None:
if self.ptr and self.subtitle_header_set:
lib.av_freep(cython.address(self.ptr.subtitle_header))
def encode_subtitle(self, subtitle: SubtitleSet) -> Packet:
"""
Encode a SubtitleSet into a Packet.
Args:
subtitle: The SubtitleSet to encode
Returns:
A Packet containing the encoded subtitle data
"""
if not self.codec.ptr:
raise ValueError("Cannot encode with unknown codec")
self.open(strict=False)
buf: cython.p_uchar = cython.cast(cython.p_uchar, lib.av_malloc(1024 * 1024))
if buf == cython.NULL:
raise MemoryError()
ret: cython.int = lib.avcodec_encode_subtitle(
self.ptr,
buf,
1024 * 1024,
cython.address(subtitle.proxy.struct),
)
if ret < 0:
lib.av_free(buf)
err_check(ret, "avcodec_encode_subtitle()")
packet: Packet = Packet(ret)
memcpy(packet.ptr.data, buf, ret)
lib.av_free(buf)
packet.ptr.pts = subtitle.proxy.struct.pts
packet.ptr.dts = subtitle.proxy.struct.pts
packet.ptr.duration = (
subtitle.proxy.struct.end_display_time
- subtitle.proxy.struct.start_display_time
)
return packet
@cython.cfunc
def _decode(self, packet: Packet | None):
"""Decode a subtitle packet, returning a list of :class:`.Subtitle` objects
if a subtitle was decoded, or an empty list otherwise."""
if not self.codec.ptr:
raise ValueError("cannot decode unknown codec")
if packet is None:
raise RuntimeError("packet cannot be None")
self.open(strict=False)
proxy: SubtitleProxy = SubtitleProxy()
got_frame: cython.int = 0
err_check(
lib.avcodec_decode_subtitle2(
self.ptr,
cython.address(proxy.struct),
cython.address(got_frame),
packet.ptr,
)
)
if got_frame:
return list(SubtitleSet(proxy))
return []
@cython.ccall
def decode2(self, packet: Packet):
"""
Returns SubtitleSet if you really need it.
"""
if not self.codec.ptr:
raise ValueError("cannot decode unknown codec")
self.open(strict=False)
proxy: SubtitleProxy = SubtitleProxy()
got_frame: cython.int = 0
err_check(
lib.avcodec_decode_subtitle2(
self.ptr,
cython.address(proxy.struct),
cython.address(got_frame),
packet.ptr,
)
)
if got_frame:
return SubtitleSet(proxy)
return None
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