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fq/format/mpeg/avc_pps.go
Mattias Wadman 2fc0a71a47 decode: Refactor scalar usage
Move scalar into own package.
Split scalar code into decode related scalar code (that reads etc) and
scalar code that just transform the scalar value.
Use a scalar.Mapper interface instead of just a function.
Make mappers, assert and validat impement the interface.
2021-12-02 17:39:26 +01:00

98 lines
2.8 KiB
Go

package mpeg
import (
"github.com/wader/fq/format"
"github.com/wader/fq/format/registry"
"github.com/wader/fq/pkg/decode"
"github.com/wader/fq/pkg/scalar"
)
func init() {
registry.MustRegister(decode.Format{
Name: format.AVC_PPS,
Description: "H.264/AVC Picture Parameter Set",
DecodeFn: avcPPSDecode,
})
}
// TODO:
// ffmpeg does: get_bits_left(gb) > 0 && show_bits(gb, 8) != 0x80
// we do: there is more than trailing rbsp left
func moreRBSPData(d *decode.D) bool {
l := d.BitsLeft()
return l > 8 //|| (l == 8 && d.PeekBits(8) != 1)
}
func avcPPSDecode(d *decode.D, in interface{}) interface{} {
d.FieldUFn("pic_parameter_set_id", uEV)
d.FieldUFn("seq_parameter_set_id", uEV)
d.FieldBool("entropy_coding_mode_flag")
d.FieldBool("bottom_field_pic_order_in_frame_present_flag")
numSliceGroups := d.FieldUFn("num_slice_groups", uEV, scalar.UAdd(1))
if numSliceGroups > 1 {
sliceGroupMapType := d.FieldUFn("slice_group_map_type", uEV)
switch sliceGroupMapType {
case 0:
d.FieldArray("slice_groups", func(d *decode.D) {
for i := uint64(0); i < numSliceGroups; i++ {
d.FieldUFn("slice_group", uEV)
}
})
case 2:
d.FieldArray("slice_groups", func(d *decode.D) {
for i := uint64(0); i < numSliceGroups; i++ {
d.FieldStruct("slice_group", func(d *decode.D) {
d.FieldUFn("top_left", uEV)
d.FieldUFn("bottom_right", uEV)
})
}
})
case 3, 4, 5:
d.FieldArray("slice_groups", func(d *decode.D) {
for i := uint64(0); i < numSliceGroups; i++ {
d.FieldStruct("slice_group", func(d *decode.D) {
d.FieldBool("change_direction_flag")
d.FieldUFn("change_rate", uEV, scalar.UAdd(1))
})
}
})
case 6:
picSizeInMapUnits := d.FieldUFn("pic_size_in_map_units", uEV, scalar.UAdd(1))
for i := uint64(0); i < picSizeInMapUnits; i++ {
d.FieldStruct("slice_group", func(d *decode.D) {
d.FieldBool("id")
})
}
}
}
d.FieldUFn("num_ref_idx_l0_default_active", uEV, scalar.UAdd(1))
d.FieldUFn("num_ref_idx_l1_default_active", uEV, scalar.UAdd(1))
d.FieldBool("weighted_pred_flag")
d.FieldU2("weighted_bipred_idc")
d.FieldSFn("pic_init_qp", sEV, scalar.SAdd(26))
d.FieldSFn("pic_init_qs", sEV, scalar.SAdd(26))
d.FieldSFn("chroma_qp_index_offset", sEV)
d.FieldBool("deblocking_filter_control_present_flag")
d.FieldBool("constrained_intra_pred_flag")
d.FieldBool("redundant_pic_cnt_present_flag")
// TODO: more_data() is there non-zero bits left?
if moreRBSPData(d) {
d.FieldBool("transform_8x8_mode_flag")
picScalingMatrixPresentFlag := d.FieldBool("pic_scaling_matrix_present_flag")
if picScalingMatrixPresentFlag {
d.FieldArray("pic_scaling_list", func(d *decode.D) {
for i := 0; i < 6; i++ {
d.Bool()
}
})
}
d.FieldSFn("second_chroma_qp_index_offset", sEV)
}
d.FieldRawLen("rbsp_trailing_bits", d.BitsLeft())
return nil
}