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Extend avc1 to support multiple video sample description extensions #6

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38 changes: 25 additions & 13 deletions src/pymp4/parser.py
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Original file line number Diff line number Diff line change
Expand Up @@ -332,6 +332,30 @@ def _encode(self, obj, context):
return obj & 0x1F


VideoSampleEntryExtensionBox = PrefixedIncludingSize(Int32ub, Struct(
"type" / String(4, padchar=b" ", paddir="right"),
Embedded(Switch(this.type, {
b"avcC": Struct(
"version" / Const(Int8ub, 1),
"profile" / Int8ub,
"compatibility" / Int8ub,
"level" / Int8ub,
EmbeddedBitStruct(
Padding(6, pattern=b'\x01'),
"nal_unit_length_field" / Default(BitsInteger(2), 3),
),
"sps" / Default(PrefixedArray(MaskedInteger(Int8ub), PascalString(Int16ub)), []),
"pps" / Default(PrefixedArray(Int8ub, PascalString(Int16ub)), []),
# if profile_idc takes specific values there can be additional information - ignoring
GreedyBytes
),
b"pasp": Struct(
"h_spacing" / Int32ub,
"v_spacing" /Int32ub
)
}, default=Struct(RawBox))),
))

AVC1SampleEntryBox = Struct(
"version" / Default(Int16ub, 0),
"revision" / Const(Int16ub, 0),
Expand All @@ -349,19 +373,7 @@ def _encode(self, obj, context):
"compressor_name" / Default(String(32, padchar=b" "), ""),
"depth" / Default(Int16ub, 24),
"color_table_id" / Default(Int16sb, -1),
"avc_data" / PrefixedIncludingSize(Int32ub, Struct(
"type" / Const(b"avcC"),
"version" / Const(Int8ub, 1),
"profile" / Int8ub,
"compatibility" / Int8ub,
"level" / Int8ub,
EmbeddedBitStruct(
Padding(6, pattern=b'\x01'),
"nal_unit_length_field" / Default(BitsInteger(2), 3),
),
"sps" / Default(PrefixedArray(MaskedInteger(Int8ub), PascalString(Int16ub)), []),
"pps" / Default(PrefixedArray(Int8ub, PascalString(Int16ub)), [])
))
"extensions" / GreedyRange(VideoSampleEntryExtensionBox),
)


Expand Down
25 changes: 24 additions & 1 deletion tests/test_box.py
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Original file line number Diff line number Diff line change
Expand Up @@ -16,9 +16,10 @@
"""
import logging
import unittest
import io

from construct import Container
from pymp4.parser import Box
from pymp4.parser import Box, SampleEntryBox

log = logging.getLogger(__name__)

Expand Down Expand Up @@ -103,3 +104,25 @@ def test_moov_build(self):
b'\x00\x00\x00\x20trex\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
b'\x00\x00\x00\x20trex\x00\x00\x00\x00\x00\x00\x00\x02\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
)

def test_avc1_parse(self):
compressor = b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
sps = b'\x67\x4d\x40\x29\xe8\x80\x28\x02\xdd\xff\x80\x0d\x80\x0a\x08\x00\x00\x1f\x48\x00\x05\xdc\x00\x78\xc1\x88\x90'
pps = b'\x68\xeb\x8c\xb2'
input_bytes = (
b'\x00\x00\x00\x98avc1\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x05\x00\x02\xd0\x00\x48\x00\x00\x00\x48\x00\x00\x00\x00\x00\x00\x00\x01' + compressor + b'\x00\x18\xff\xff'
b'\x00\x00\x00\x32avcC\x01\x4d\x40\x29\xff\xe1\x00\x1b' + sps + b'\x01\x00\x04' + pps +
b'\x00\x00\x00\x10pasp\x00\x00\x00\x1b\x00\x00\x00\x14'
)
expected = (
Container(format=b'avc1')(data_reference_index=1)(version=0)(revision=0)(vendor=b'\x00\x00\x00\x00')
(temporal_quality=0)(spatial_quality=0)(width=1280)(height=720)(horizontal_resolution=72)
(vertical_resolution=72)(data_size=0)(frame_count=1)(compressor_name=compressor)(depth=24)(color_table_id=-1)
(extensions=[
Container(type=b'avcC')(version=1)(profile=77)(compatibility=64)(level=41)(nal_unit_length_field=3)(sps=[sps])(pps=[pps]),
Container(type=b'pasp')(h_spacing=27)(v_spacing=20)
])
)
input_stream = io.BytesIO(input_bytes + b'padding')
self.assertEqual(SampleEntryBox.parse_stream(input_stream), expected)
self.assertEqual(input_stream.tell(), len(input_bytes))