demuxer, decoder not working

This commit is contained in:
2025-10-03 15:10:49 +02:00
parent 3c56a880da
commit 2316435af8
6 changed files with 176 additions and 78 deletions

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@ -1,54 +0,0 @@
# RozK
from . import libav
from .codec import Codec
from .stream import NullStream, Stream
from .packet import Packet
class Context:
__slots__ = '_ref'
def __init__(self):
self._ref = libav.alloc_context()
if not self._ref:
raise MemoryError
def __del__(self):
if self._ref:
libav.free_context(self._ref)
@property
def _as_parameter_(self):
return self._ref
def open_input(self, url):
if not self._ref:
return
errcode = libav.open_input(self._ref, url)
if errcode < 0:
raise Exception(f"Failed to open: {url}")
errcode = libav.find_stream_info(self._ref)
if errcode < 0:
libav.close_input(self._ref)
raise Exception("Failed to find stream info")
def close_input(self):
if self._ref:
libav.close_input(self._ref)
def find_stream(self, type):
if not self._ref:
return NullStream()
index, codec_ref = libav.find_best_stream(self._ref, type)
if index < 0 or not codec_ref:
return NullStream()
return Stream(index, Codec(codec_ref))
def read_packet(self):
if not self._ref:
return None
packet = Packet()
errcode = libav.read_frame(self._ref, packet)
if errcode < 0:
return None
return packet

46
mp4/decoder.py Normal file
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@ -0,0 +1,46 @@
# RozK
import errno
from . import libav
from .frame import Frame
class Decoder:
__slots__ = '_ref'
def __init__(self, codec):
self._ref = libav.codec_alloc_context(codec)
if not self._ref:
raise MemoryError
errcode = libav.codec_open(self._ref, codec)
if errcode < 0:
libav.codec_free_context(self._ref)
raise Exception("Failed to open codec context")
def __del__(self):
if self._ref:
libav.codec_free_context(self._ref)
def _recieve(self, frames):
while True:
frame = Frame()
errcode = libav.codec_receive_frame(self._ref, frame)
if errcode == 0:
frames.append(frame)
elif errcode == errno.EAGAIN:
break
else:
raise Exception(f"Failed to receive frame: {errcode}")
def decode(self, packet):
if not self._ref:
return None
frames = []
while True:
errcode = libav.codec_send_packet(self._ref, packet)
if errcode != 0 and errcode != errno.EAGAIN:
raise Exception(f"Failed to send packet: {errcode}")
self._recieve(frames)
if errcode == 0:
break
return frames

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@ -1,19 +1,42 @@
# RozK
from . import libav
from .context import Context
from .codec import Codec
from .stream import NullStream, Stream
from .packet import Packet
class Demuxer:
__slots__ = 'context', 'video_stream', 'audio_stream'
__slots__ = '_ref', 'video_stream', 'audio_stream'
def __init__(self, path):
self.context = Context()
self.context.open_input("file:" + path)
self.video_stream = self.context.find_stream(libav.AVMEDIA_TYPE_VIDEO)
self.audio_stream = self.context.find_stream(libav.AVMEDIA_TYPE_AUDIO)
self._ref = libav.format_alloc_context()
if not self._ref:
raise MemoryError
errcode = libav.format_open_input(self._ref, "file:" + path)
if errcode < 0:
raise Exception(f"Failed to open: {path}")
errcode = libav.format_find_stream_info(self._ref)
if errcode < 0:
libav.format_close_input(self._ref)
raise Exception("Failed to find stream info")
self.video_stream = self._find_stream(libav.AVMEDIA_TYPE_VIDEO)
self.audio_stream = self._find_stream(libav.AVMEDIA_TYPE_AUDIO)
def _find_stream(self, type):
index, codec_ref = libav.format_find_best_stream(self._ref, type)
if index < 0 or not codec_ref:
return NullStream()
return Stream(index, Codec(codec_ref))
def read_packet(self):
return self.context.read_packet()
if not self._ref:
return None
packet = Packet()
errcode = libav.read_frame(self._ref, packet)
if errcode < 0:
return None
return packet
def close(self):
self.context.close_input()
if self._ref:
libav.format_close_input(self._ref)

19
mp4/frame.py Normal file
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@ -0,0 +1,19 @@
# RozK
from . import libav
class Frame:
__slots__ = '_ref'
def __init__(self):
self._ref = libav.frame_alloc()
if not self._ref:
raise MemoryError
def __del__(self):
if self._ref:
libav.frame_free(self._ref)
@property
def _as_parameter_(self):
return self._ref

View File

@ -3,9 +3,28 @@
import ctypes
_avutil = ctypes.cdll.LoadLibrary('libavutil.so')
_avformat = ctypes.cdll.LoadLibrary('libavformat.so')
_avcodec = ctypes.cdll.LoadLibrary('libavcodec.so')
class AVFrame(ctypes.Structure):
pass
AVFrame_p = ctypes.POINTER(AVFrame)
AVFrame_pp = ctypes.POINTER(AVFrame_p)
_avutil.av_frame_alloc.restype = AVFrame_p
_avutil.av_frame_alloc.argtypes = None
def frame_alloc():
return _avutil.av_frame_alloc()
_avutil.av_frame_free.restype = None
_avutil.av_frame_free.argtypes = [AVFrame_pp]
def frame_free(frame):
_avutil.av_frame_free(ctypes.byref(frame))
class AVFormatContext(ctypes.Structure):
pass
@ -15,37 +34,37 @@ AVFormatContext_pp = ctypes.POINTER(AVFormatContext_p)
_avformat.avformat_alloc_context.restype = AVFormatContext_p
_avformat.avformat_alloc_context.argtypes = None
def alloc_context():
def format_alloc_context():
return _avformat.avformat_alloc_context()
_avformat.avformat_free_context.restype = None
_avformat.avformat_free_context.argtypes = [AVFormatContext_p] # context
_avformat.avformat_free_context.argtypes = [AVFormatContext_p]
def free_context(context):
def format_free_context(context):
_avformat.avformat_free_context(context)
_avformat.avformat_open_input.restype = ctypes.c_int
_avformat.avformat_open_input.argtypes = [
AVFormatContext_pp, # context
AVFormatContext_pp,
ctypes.c_char_p, # url
ctypes.c_void_p, # format
ctypes.POINTER(ctypes.c_void_p)] # options
def open_input(context, url):
def format_open_input(context, url):
return _avformat.avformat_open_input(ctypes.byref(context), url.encode('ascii', 'ignore'), None, None)
_avformat.avformat_close_input.restype = None
_avformat.avformat_close_input.argtypes = [AVFormatContext_pp] # context
_avformat.avformat_close_input.argtypes = [AVFormatContext_pp]
def close_input(context):
def format_close_input(context):
_avformat.avformat_close_input(ctypes.byref(context))
_avformat.avformat_find_stream_info.restype = ctypes.c_int
_avformat.avformat_find_stream_info.argtypes = [
AVFormatContext_p, # context
AVFormatContext_p,
ctypes.POINTER(ctypes.c_void_p)] # options
def find_stream_info(context):
def format_find_stream_info(context):
return _avformat.avformat_find_stream_info(context, None)
AVMEDIA_TYPE_UNKNOWN = -1
@ -66,14 +85,14 @@ AVCodec_pp = ctypes.POINTER(AVCodec_p)
_avformat.av_find_best_stream.restype = ctypes.c_int
_avformat.av_find_best_stream.argtypes = [
AVFormatContext_p, # context
AVFormatContext_p,
ctypes.c_int, # type
ctypes.c_int, # wanted stream
ctypes.c_int, # related stream
AVCodec_pp, # decoder
AVCodec_pp,
ctypes.c_int] # flags
def find_best_stream(context, type):
def format_find_best_stream(context, type):
codec = AVCodec_p()
index = _avformat.av_find_best_stream(context, type, -1, -1, ctypes.byref(codec), 0)
return index, codec
@ -98,15 +117,52 @@ def packet_alloc():
return _avformat.av_packet_alloc()
_avformat.av_packet_free.restype = None
_avformat.av_packet_free.argtypes = [AVPacket_pp] # packet
_avformat.av_packet_free.argtypes = [AVPacket_pp]
def packet_free(packet):
_avformat.av_packet_free(ctypes.byref(packet))
_avformat.av_read_frame.restype = ctypes.c_int
_avformat.av_read_frame.argtypes = [
AVFormatContext_p, # context
AVPacket_p] # packet
_avformat.av_read_frame.argtypes = [AVFormatContext_p, AVPacket_p]
def read_frame(context, packet):
return _avformat.av_read_frame(context, packet)
class AVCodecContext(ctypes.Structure):
pass
AVCodecContext_p = ctypes.POINTER(AVCodecContext)
AVCodecContext_pp = ctypes.POINTER(AVCodecContext_p)
_avcodec.avcodec_alloc_context3.restype = AVCodecContext_p
_avcodec.avcodec_alloc_context3.argtypes = [AVCodec_p]
def codec_alloc_context(codec):
return _avcodec.avcodec_alloc_context3(codec)
_avcodec.avcodec_free_context.restype = None
_avcodec.avcodec_free_context.argtypes = [AVCodecContext_pp]
def codec_free_context(context):
_avcodec.avcodec_free_context(ctypes.byref(context))
_avcodec.avcodec_open2.restype = ctypes.c_int
_avcodec.avcodec_open2.argtypes = [
AVCodecContext_p,
AVCodec_p,
ctypes.POINTER(ctypes.c_void_p)] # options
def codec_open(context, codec):
return _avcodec.avcodec_open2(context, codec, None)
_avcodec.avcodec_send_packet.restype = ctypes.c_int
_avcodec.avcodec_send_packet.argtypes = [AVCodecContext_p, AVPacket_p]
def codec_send_packet(context, packet):
return _avcodec.avcodec_send_packet(context, packet)
_avcodec.avcodec_receive_frame.restype = ctypes.c_int
_avcodec.avcodec_receive_frame.argtypes = [AVCodecContext_p, AVFrame_p]
def codec_receive_frame(context, frame):
return _avcodec.avcodec_receive_frame(context, frame)

8
pve.py
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@ -1,19 +1,27 @@
# RozK
from mp4.demuxer import Demuxer
from mp4.decoder import Decoder
demuxer = Demuxer('test.mp4')
print(demuxer.video_stream.codec.name)
print(demuxer.audio_stream.codec.name)
video_decoder = Decoder(demuxer.video_stream.codec)
audio_decoder = Decoder(demuxer.audio_stream.codec)
while True:
packet = demuxer.read_packet()
if packet is None:
break
if demuxer.video_stream.contains(packet):
video_frames = video_decoder.decode(packet)
print(f"decoded {len(video_frames)} video frames")
continue
elif demuxer.audio_stream.contains(packet):
audio_frames = audio_decoder.decode(packet)
print(f"decoded {len(audio_frames)} audio frames")
continue
else:
print("unkown packet")