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mirror of https://github.com/wader/fq.git synced 2024-12-25 22:34:14 +03:00
fq/format/mpeg/avc_pps.go
2021-09-12 13:08:50 +02:00

97 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"
)
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{} {
fieldUEV(d, "pic_parameter_set_id")
fieldUEV(d, "seq_parameter_set_id")
d.FieldBool("entropy_coding_mode_flag")
d.FieldBool("bottom_field_pic_order_in_frame_present_flag")
numSliceGroupsMinus1 := fieldUEV(d, "num_slice_groups_minus1")
if numSliceGroupsMinus1 > 0 {
sliceGroupMapType := fieldUEV(d, "slice_group_map_type")
switch sliceGroupMapType {
case 0:
d.FieldArrayFn("slice_groups", func(d *decode.D) {
for i := uint64(0); i <= numSliceGroupsMinus1; i++ {
fieldUEV(d, "slice_group")
}
})
case 2:
d.FieldArrayFn("slice_groups", func(d *decode.D) {
for i := uint64(0); i <= numSliceGroupsMinus1; i++ {
d.FieldStructFn("slice_group", func(d *decode.D) {
fieldUEV(d, "top_left")
fieldUEV(d, "bottom_right")
})
}
})
case 3, 4, 5:
d.FieldArrayFn("slice_groups", func(d *decode.D) {
for i := uint64(0); i <= numSliceGroupsMinus1; i++ {
d.FieldStructFn("slice_group", func(d *decode.D) {
d.FieldBool("change_direction_flag")
fieldUEV(d, "change_rate_minus1")
})
}
})
case 6:
picSizeInMapUnitsMinus1 := fieldUEV(d, "pic_size_in_map_units_minus1")
for i := uint64(0); i <= picSizeInMapUnitsMinus1; i++ {
d.FieldStructFn("slice_group", func(d *decode.D) {
d.FieldBool("id")
})
}
}
}
fieldUEV(d, "num_ref_idx_l0_default_active_minus1")
fieldUEV(d, "num_ref_idx_l1_default_active_minus1")
d.FieldBool("weighted_pred_flag")
d.FieldU2("weighted_bipred_idc")
fieldSEV(d, "pic_init_qp_minus26") /* relative to 26 */
fieldSEV(d, "pic_init_qs_minus26") /* relative to 26 */
fieldSEV(d, "chroma_qp_index_offset")
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.FieldArrayFn("pic_scaling_list", func(d *decode.D) {
for i := 0; i < 6; i++ {
d.Bool()
}
})
}
fieldSEV(d, "second_chroma_qp_index_offset")
}
d.FieldBitBufLen("rbsp_trailing_bits", d.BitsLeft())
return nil
}