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h265: cleanup DTS extractor (#75)
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@aler9
aler9 authored Sep 2, 2023
1 parent 8b3f6aa commit 93f9c90
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Showing 2 changed files with 107 additions and 40 deletions.
61 changes: 22 additions & 39 deletions pkg/codecs/h265/dts_extractor.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -8,9 +8,9 @@ import (
"github.com/bluenviron/mediacommon/pkg/codecs/h264"
)

func getPictureOrderCount(buf []byte, sps *SPS, pps *PPS) (uint32, uint32, error) {
func getPTSDTSDiff(buf []byte, sps *SPS, pps *PPS) (uint32, error) {
if len(buf) < 12 {
return 0, 0, fmt.Errorf("not enough bits")
return 0, fmt.Errorf("not enough bits")
}

buf = h264.EmulationPreventionRemove(buf[:12])
Expand All @@ -22,70 +22,70 @@ func getPictureOrderCount(buf []byte, sps *SPS, pps *PPS) (uint32, uint32, error

firstSliceSegmentInPicFlag, err := bits.ReadFlag(buf, &pos)
if err != nil {
return 0, 0, err
return 0, err
}

if !firstSliceSegmentInPicFlag {
return 0, 0, fmt.Errorf("first_slice_segment_in_pic_flag = 0 is not supported")
return 0, fmt.Errorf("first_slice_segment_in_pic_flag = 0 is not supported")
}

if typ >= NALUType_BLA_W_LP && typ <= NALUType_RSV_IRAP_VCL23 {
_, err := bits.ReadFlag(buf, &pos) // no_output_of_prior_pics_flag
if err != nil {
return 0, 0, err
return 0, err
}
}

_, err = bits.ReadGolombUnsigned(buf, &pos) // slice_pic_parameter_set_id
if err != nil {
return 0, 0, err
return 0, err
}

if pps.NumExtraSliceHeaderBits > 0 {
err := bits.HasSpace(buf, pos, int(pps.NumExtraSliceHeaderBits))
if err != nil {
return 0, 0, err
return 0, err
}
pos += int(pps.NumExtraSliceHeaderBits)
}

sliceType, err := bits.ReadGolombUnsigned(buf, &pos) // slice_type
if err != nil {
return 0, 0, err
return 0, err
}

if pps.OutputFlagPresentFlag {
_, err := bits.ReadFlag(buf, &pos) // pic_output_flag
if err != nil {
return 0, 0, err
return 0, err
}
}

if sps.SeparateColourPlaneFlag {
_, err := bits.ReadBits(buf, &pos, 2) // colour_plane_id
if err != nil {
return 0, 0, err
return 0, err
}
}

picOrderCntLsb, err := bits.ReadBits(buf, &pos, int(sps.Log2MaxPicOrderCntLsbMinus4+4))
_, err = bits.ReadBits(buf, &pos, int(sps.Log2MaxPicOrderCntLsbMinus4+4)) // pic_order_cnt_lsb
if err != nil {
return 0, 0, err
return 0, err
}

shortTermRefPicSetSpsFlag, err := bits.ReadFlag(buf, &pos)
if err != nil {
return 0, 0, err
return 0, err
}

if shortTermRefPicSetSpsFlag {
return 0, 0, fmt.Errorf("short_term_ref_pic_set_sps_flag = true is not supported")
return 0, fmt.Errorf("short_term_ref_pic_set_sps_flag = true is not supported")
}

var rps SPS_ShortTermRefPicSet
err = rps.unmarshal(buf, &pos, uint32(len(sps.ShortTermRefPicSets)), uint32(len(sps.ShortTermRefPicSets)), nil)
if err != nil {
return 0, 0, err
return 0, err
}

var v uint32
Expand All @@ -95,30 +95,18 @@ func getPictureOrderCount(buf []byte, sps *SPS, pps *PPS) (uint32, uint32, error
v = sps.MaxNumReorderPics[0] - uint32(len(rps.DeltaPocS1Minus1))
} else if typ == NALUType_TRAIL_R || typ == NALUType_RASL_R {
if len(rps.DeltaPocS0Minus1) == 0 {
return 0, 0, fmt.Errorf("invalid delta_poc_s0_minus1")
return 0, fmt.Errorf("invalid delta_poc_s0_minus1")
}
v = rps.DeltaPocS0Minus1[0] + sps.MaxNumReorderPics[0] - 1
}
} else { // I or P-frame
if len(rps.DeltaPocS0Minus1) == 0 {
return 0, 0, fmt.Errorf("invalid delta_poc_s0_minus1")
return 0, fmt.Errorf("invalid delta_poc_s0_minus1")
}
v = rps.DeltaPocS0Minus1[0] + sps.MaxNumReorderPics[0]
}

dtsPOC := uint32(picOrderCntLsb) - v
dtsPOC &= ((1 << (sps.Log2MaxPicOrderCntLsbMinus4 + 4)) - 1)

return uint32(picOrderCntLsb), dtsPOC, nil
}

func getPictureOrderCountDiff(a uint32, b uint32, sps *SPS) int32 {
max := uint32(1 << (sps.Log2MaxPicOrderCntLsbMinus4 + 4))
d := (a - b) & (max - 1)
if d > (max / 2) {
return int32(d) - int32(max)
}
return int32(d)
return v, nil
}

// DTSExtractor allows to extract DTS from PTS.
Expand All @@ -140,7 +128,6 @@ func (d *DTSExtractor) extractInner(au [][]byte, pts time.Duration) (time.Durati

for _, nalu := range au {
typ := NALUType((nalu[0] >> 1) & 0b111111)

switch typ {
case NALUType_SPS_NUT:
var spsp SPS
Expand Down Expand Up @@ -182,18 +169,15 @@ func (d *DTSExtractor) extractInner(au [][]byte, pts time.Duration) (time.Durati
return pts, nil
}

var poc uint32
var dtsPOC uint32
var samplesDiff uint32

switch {
case idr != nil:
poc = 0
dtsPOC = poc - 2
dtsPOC &= ((1 << (d.spsp.Log2MaxPicOrderCntLsbMinus4 + 4)) - 1)
samplesDiff = d.spsp.MaxNumReorderPics[0]

case nonIDR != nil:
var err error
poc, dtsPOC, err = getPictureOrderCount(nonIDR, d.spsp, d.ppsp)
samplesDiff, err = getPTSDTSDiff(nonIDR, d.spsp, d.ppsp)
if err != nil {
return 0, err
}
Expand All @@ -202,8 +186,7 @@ func (d *DTSExtractor) extractInner(au [][]byte, pts time.Duration) (time.Durati
return 0, fmt.Errorf("access unit doesn't contain an IDR or non-IDR NALU")
}

pocDiff := getPictureOrderCountDiff(poc, dtsPOC, d.spsp)
timeDiff := time.Duration(pocDiff) * time.Second *
timeDiff := time.Duration(samplesDiff) * time.Second *
time.Duration(d.spsp.VUI.TimingInfo.NumUnitsInTick) / time.Duration(d.spsp.VUI.TimingInfo.TimeScale)
dts := pts - timeDiff

Expand Down
86 changes: 85 additions & 1 deletion pkg/codecs/h265/dts_extractor_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,91 @@ func TestDTSExtractor(t *testing.T) {
sequence []sequenceSample
}{
{
"no timing info",
"with timing info, IDR",
[]sequenceSample{
{
[][]byte{
{ // VPS
0x40, 0x01, 0x0c, 0x01, 0xff, 0xff, 0x01, 0x60,
0x00, 0x00, 0x03, 0x00, 0x90, 0x00, 0x00, 0x03,
0x00, 0x00, 0x03, 0x00, 0x78, 0x99, 0x98, 0x09,
},
{ // SPS
0x42, 0x01, 0x01, 0x01, 0x60, 0x00, 0x00, 0x03,
0x00, 0x90, 0x00, 0x00, 0x03, 0x00, 0x00, 0x03,
0x00, 0x78, 0xa0, 0x03, 0xc0, 0x80, 0x10, 0xe5,
0x96, 0x66, 0x69, 0x24, 0xca, 0xe0, 0x10, 0x00,
0x00, 0x03, 0x00, 0x10, 0x00, 0x00, 0x03, 0x01,
0xe0, 0x80,
},
{ // PPS
0x44, 0x1, 0xc1, 0x72, 0xb4, 0x62, 0x40,
},
{ // IDR_W_RADL
0x26, 0x1, 0xaf, 0x8, 0x42, 0x23, 0x48, 0x8a, 0x43, 0xe2,
},
},
0,
-66666666 * time.Nanosecond,
},
{
[][]byte{{ // TRAIL_R
0x02, 0x01, 0xd0, 0x19, 0x5f, 0x8c, 0xb4, 0x42,
0x49, 0x20, 0x40, 0x11, 0x16, 0x92, 0x93, 0xea,
0x54, 0x57, 0x4e, 0x0a,
}},
100 * time.Millisecond,
-33333333 * time.Nanosecond,
},
{
[][]byte{{ // TRAIL_R
0x02, 0x01, 0xe0, 0x44, 0x97, 0xe0, 0x81, 0x20,
0x44, 0x52, 0x62, 0x7a, 0x1b, 0x88, 0x0b, 0x21,
0x26, 0x5f, 0x10, 0x9c,
}},
66666666 * time.Nanosecond,
0,
},
{
[][]byte{{ // TRAIL_N
0x00, 0x01, 0xe0, 0x24, 0xff, 0xfa, 0x24, 0x0a,
0x42, 0x25, 0x8c, 0x18, 0xe6, 0x1c, 0xea, 0x5a,
0x5d, 0x07, 0xc1, 0x8f,
}},
33333333 * time.Nanosecond,
33333333 * time.Nanosecond,
},
{
[][]byte{{ // TRAIL_R
0x02, 0x01, 0xd0, 0x30, 0x97, 0xd7, 0xdc, 0xf9,
0x0c, 0x10, 0x11, 0x11, 0x20, 0x42, 0x11, 0x18,
0x63, 0xa5, 0x18, 0x55,
}},
200 * time.Millisecond,
66666667 * time.Nanosecond,
},
{
[][]byte{{ // TRAIL_R
0x02, 0x01, 0xe0, 0xa2, 0x25, 0xd7, 0xf7, 0x08,
0x12, 0x04, 0x45, 0xa1, 0x83, 0xc0, 0x97, 0x53,
0xa3, 0x5e, 0x78, 0x14,
}},
166666666 * time.Nanosecond,
100 * time.Millisecond,
},
{
[][]byte{{ // TRAIL_N
0x00, 0x01, 0xe0, 0x82, 0x3f, 0x5f, 0xf6, 0x89,
0x02, 0x90, 0x88, 0xa3, 0x0c, 0x7d, 0x27, 0x0c,
0xd4, 0xd9, 0xc2, 0xa5,
}},
133333333 * time.Nanosecond,
133333333 * time.Nanosecond,
},
},
},
{
"no timing info, CRA",
[]sequenceSample{
{
[][]byte{
Expand Down

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