def find_video_configuration_at(file, stbl_pos=None):
# STBL.STSD.[AVC1 | HEC1 | HVC1].[AVCC | HVCC]
pos, _, _, header_size = next(find_headers_at(file, {b"stbl"}, stbl_pos))
pos, _, _, header_size = next(
find_headers_at(file, {b"stsd"}, pos + header_size))
header_size += (
1 + # version (fullbox): 1 bytes
3 + # flags (fullbox): 24 bits
4) # entry_count: uint32
__c1 = next(
find_headers_at(file, {b"avc1", b"hec1", b"hvc1"}, pos + header_size),
None)
if __c1 is None:
return None
pos, _, _, header_size = __c1
_vcC_offset = (
header_size + 6 + # reserved: 48 bits
2 + # data_reference_index: uint16
2 + # pre_defined: 16 bits
2 + # reserved: 16 bits
12 + # pre_defined: 96 bits
2 + # width: uint16
2 + # height: uint16
4 + # horizresolution: 2 * uint16
4 + # vertresolution: 2 * uint16
4 + # reserved: 32 bits
2 + # frame_count: uint16
32 + # compressorname: 32 bytes
2 + # depth: uint16
2) # pre_defined: 16 bits
return next(find_headers_at(file, {b"avcC", b"hvcC"}, pos + _vcC_offset))
def find_sample_table_at(file, trak_pos=None):
# TRAK.MDIA.MINF.STBL
pos, _, _, header_size = next(find_headers_at(file, {b"trak"}, trak_pos))
pos, _, _, header_size = next(
find_headers_at(file, {b"mdia"}, pos + header_size))
pos, _, _, header_size = next(
find_headers_at(file, {b"minf"}, pos + header_size))
return next(find_headers_at(file, {b"stbl"}, pos + header_size))
def get_name_at(file, trak_pos=None):
# TRAK.MDIA.HDLR
pos, _, _, header_size = next(find_headers_at(file, {b"trak"}, trak_pos))
pos, _, _, header_size = next(find_headers_at(file, {b"mdia"}, pos + header_size))
pos, box_size, _, header_size = next(find_headers_at(file, {b"hdlr"}, pos + header_size))
name_offset = (header_size +
1 + # version (fullbox): 1 bytes
3 + # flag (fullbox)s: 24 bits
4 + # pre_defined: uint32
4 + # handler_type: 4 bytes
12) # reserved0: 3 * 32 bits
file.seek(pos + name_offset)
return file.read(box_size - name_offset)
def get_chunk_offset_at(file, stbl_pos=None):
# STBL.[STCO | CO64]
pos, _, _, header_size = next(find_headers_at(file, {b"stbl"}, stbl_pos))
pos, box_size, box_type, header_size = \
next(find_headers_at(file, {b"stco", b"co64"}, pos + header_size))
header_size += (
1 + # version (fullbox): 1 bytes
3) # flags (fullbox): 24 bits
file.seek(pos + header_size + 4) # entry_count: uint32
co_buf = file.read(box_size - header_size - 4) # entry_count: uint32
co = np.frombuffer(
co_buf,
np.dtype(">u4") if box_type == b"stco" else np.dtype(">u8"))
return co, co_buf
def test_find_headers_at():
creation_time = utils.to_mp4_time(datetime(2019, 9, 15, 0, 0, 0))
modification_time = utils.to_mp4_time(datetime(2019, 9, 16, 0, 0, 0))
samples_sizes = [198297, 127477, 192476]
samples_offset = 10
trak = utils.make_trak(creation_time, modification_time, samples_sizes,
samples_offset)
# MOOV.TRAK.TKHD
tkhd = trak.boxes[0]
tkhd.track_id = 1
tkhd.width = [512, 0]
tkhd.height = [512, 0]
trak.refresh_box_size()
buffer = io.BytesIO(bytes(trak))
for (pos, box_size, box_type, header_size), \
box in zip(utils.find_headers_at(buffer, {b'tkhd', b'mdia'},
offset=trak.header.header_size),
utils.find_boxes(trak.boxes, {b'tkhd', b'mdia'})):
assert pos < buffer.tell()
assert box_size == box.header.box_size
assert box_type == box.header.type
if isinstance(box.header, hd_def.FullBoxHeader):
assert header_size + 4 == box.header.header_size
else:
assert header_size == box.header.header_size
def get_sample_size_at(file, stbl_pos=None):
# STBL.STSZ
pos, _, _, header_size = next(find_headers_at(file, {b"stbl"}, stbl_pos))
pos, box_size, box_type, header_size = \
next(find_headers_at(file, {b"stsz"}, pos + header_size))
header_size += (1 + # version (fullbox): 1 bytes
3) # flags (fullbox): 24 bits
file.seek(pos)
stsz_buf = file.read(box_size)
sample_size = int.from_bytes(stsz_buf[header_size:header_size + 4], "big")
if sample_size > 0:
sz_buf = stsz_buf[header_size:header_size + 4]
else:
sz_buf = stsz_buf[header_size +
4 + # sample_size: uint32
4:] # sample_count: uint32
sz = np.frombuffer(sz_buf, np.dtype(">u4"))
return sz, sz_buf
def get_shape_at(file, trak_pos=None):
# TRAK.TKHD
pos, _, _, header_size = next(find_headers_at(file, {b"trak"}, trak_pos))
pos, box_size, _, header_size = next(find_headers_at(file, {b"tkhd"}, pos + header_size))
file.seek(pos)
box_buf = file.read(box_size)
box_version = box_buf[header_size + 0] # version (fullbox): uint8
shape_offset = (header_size +
1 + # version (fullbox): uint8
3 + # flags (fullbox): 24 bits
8 + # creation_time: uint64
8 + # modification_time: uint64
4 + # track_id: uint32
4 + # reserved0: 32 bits
8 + # duration: uint64
8 + # reserved1: 2 * 32 bits
2 + # layer: uint16
2 + # alternate_group: uint16
2 + # volume: 2 * uint8
2 + # reserved2: 16 bits
36) # matrix: 9 * uint32
if box_version != 1:
shape_offset += ((4 - 8) + # creation_time: uint32
(4 - 8) + # modification_time: uint32
(4 - 4) + # track_id: uint32
(4 - 4) + # reserved0: 32 bi32
(4 - 8)) # duration: uint32
width_offset = shape_offset
height_offset = shape_offset + 4 # width: 2 * uint16
# Read only integer parts of width and height
# (width and height are uint16.uint16 floats)
width = int.from_bytes(box_buf[width_offset:width_offset + 2], "big")
height = int.from_bytes(box_buf[height_offset:height_offset + 2], "big")
return width, height
