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mirror of https://github.com/wader/fq.git synced 2024-11-27 06:04:47 +03:00
fq/format/vpx/vp8_frame.go
Mattias Wadman 8e0dde03d0 decode: Support multiple format args and some rename and refactor
This will allow passing both cli options and format options to sub decoder.
Ex: pass keylog option to a tls decoder when decoding a pcap.
Ex: pass decode options to a format inside a http body inside a pcap.

Add ArgAs method to lookup argument based on type. This also makes the format
decode function have same signature as sub decoders in the decode API.

This change decode.Format a bit:
DecodeFn is now just func(d *D) any
DecodeInArg renamed to DefaultInArg
2023-02-18 21:38:51 +01:00

72 lines
1.7 KiB
Go

package vpx
// https://tools.ietf.org/html/rfc6386
import (
"github.com/wader/fq/format"
"github.com/wader/fq/pkg/decode"
"github.com/wader/fq/pkg/interp"
"github.com/wader/fq/pkg/scalar"
)
// TODO: vpx frame?
func init() {
interp.RegisterFormat(decode.Format{
Name: format.VP8_FRAME,
Description: "VP8 frame",
DecodeFn: vp8Decode,
})
}
func vp8Decode(d *decode.D) any {
var isKeyFrame bool
versions := map[uint64]struct {
reconstruction string
loop string
}{
0: {"Bicubic", "Normal"},
1: {"Bilinear", "Simple"},
2: {"Bilinear", "None"},
3: {"None", "None"},
}
d.FieldStruct("tag", func(d *decode.D) {
// first_part_size is not contiguous bits
firstPartSize0 := d.FieldU3("first_part_size0")
d.FieldU1("show_frame")
version := d.FieldU3("version")
keyFrameV := d.FieldBool("frame_type", scalar.BoolMapSymStr{true: "non_key_frame", false: "key_frame"})
firstPartSize1 := d.FieldU16LE("first_part_size1")
firstPartSize := firstPartSize0 | firstPartSize1<<3
d.FieldValueUint("first_part_size", firstPartSize)
isKeyFrame = !keyFrameV
if v, ok := versions[version]; ok {
d.FieldValueStr("reconstruction", v.reconstruction)
d.FieldValueStr("loop", v.loop)
}
})
if isKeyFrame {
d.FieldU24("start_code", d.UintValidate(0x9d012a), scalar.UintHex)
// width and height are not contiguous bits
width0 := d.FieldU8("width0")
d.FieldU2("horizontal_scale")
width1 := d.FieldU6("width1")
d.FieldValueUint("width", width0|width1<<8)
height0 := d.FieldU8("height0")
d.FieldU2("vertical_scale")
height1 := d.FieldU6("height1")
d.FieldValueUint("height", height0|height1<<8)
}
d.FieldRawLen("data", d.BitsLeft())
return nil
}