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mp4: Properly use trun data offset

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Each trun has it's own data offset, before the last offset was wrongly used
for all truns. Could also cause sample ranges to be beyond EOF.

tenc: Decode default constant iv

Fixes #292
This commit is contained in:
Mattias Wadman 2022-06-07 15:34:09 +02:00
parent f7457ce893
commit 7d25fbfdbb
2 changed files with 66 additions and 30 deletions
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45
format/mp4/boxes.go
View File

@ -196,8 +196,9 @@ type moofBox struct {
}
type trafBox struct {
trackID int
moof *moof
trackID int
baseDataOffset int64
moof *moof
}
func irefEntryDecode(ctx *decodeContext, d *decode.D) {
@ -777,7 +778,8 @@ func init() {
},
"moov": decodeBoxes,
"moof": func(ctx *decodeContext, d *decode.D) {
decodeBoxesWithParentData(ctx, d, &moofBox{offset: (d.Pos() / 8) - 8})
offset := (d.Pos() / 8) - 8
decodeBoxesWithParentData(ctx, d, &moofBox{offset: offset})
},
// Track Fragment
"traf": func(ctx *decodeContext, d *decode.D) {
@ -807,7 +809,6 @@ func init() {
d.FieldU1("unused2")
sampleDescriptionIndexPresent = d.FieldBool("sample_description_index_present")
baseDataOffsetPresent = d.FieldBool("base_data_offset_present")
})
trackID := int(d.FieldU32("track_id"))
@ -815,16 +816,10 @@ func init() {
if mb := ctx.currentMoofBox(); mb != nil {
m.offset = mb.offset
}
if t := ctx.currentTrafBox(); t != nil {
t.trackID = trackID
t.moof = m
}
if t := ctx.currentTrack(); t != nil {
t.moofs = append(t.moofs, m)
}
baseDataOffset := int64(0)
if baseDataOffsetPresent {
d.FieldU64("base_data_offset")
baseDataOffset = int64(d.FieldU64("base_data_offset"))
}
if sampleDescriptionIndexPresent {
m.defaultSampleDescriptionIndex = int(d.FieldU32("sample_description_index"))
@ -838,6 +833,15 @@ func init() {
if defaultSampleFlagsPresent {
d.FieldU32("default_sample_flags")
}
if t := ctx.currentTrafBox(); t != nil {
t.trackID = trackID
t.moof = m
t.baseDataOffset = baseDataOffset
}
if t := ctx.currentTrack(); t != nil {
t.moofs = append(t.moofs, m)
}
},
// Track Fragment Run
"trun": func(ctx *decodeContext, d *decode.D) {
@ -865,8 +869,9 @@ func init() {
dataOffsetPresent = d.FieldBool("data_offset_present")
})
sampleCount := d.FieldU32("sample_count")
dataOffset := int64(0)
if dataOffsetPresent {
m.dataOffset = d.FieldS32("data_offset")
dataOffset = d.FieldS32("data_offset")
}
if firstSampleFlagsPresent {
d.FieldU32("first_sample_flags")
@ -876,6 +881,9 @@ func init() {
d.Errorf("too many sample trun entries %d > %d", sampleCount, maxSampleEntryCount)
}
t := trun{
dataOffset: dataOffset,
}
d.FieldArray("samples", func(d *decode.D) {
for i := uint64(0); i < sampleCount; i++ {
sampleSize := m.defaultSampleSize
@ -894,9 +902,11 @@ func init() {
}
})
m.samplesSizes = append(m.samplesSizes, sampleSize)
t.samplesSizes = append(t.samplesSizes, sampleSize)
}
})
m.truns = append(m.truns, t)
},
"tfdt": func(_ *decodeContext, d *decode.D) {
version := d.FieldU8("version")
@ -1244,7 +1254,9 @@ func init() {
d.FieldArray("samples", func(d *decode.D) {
for i := uint64(0); i < sampleCount; i++ {
d.FieldStruct("entry", func(d *decode.D) {
d.FieldRawLen("iv", int64(t.defaultIVSize*8))
if t.defaultIVSize != 0 {
d.FieldRawLen("iv", int64(t.defaultIVSize*8))
}
if flags&0b10 != 0 {
subSampleCount := d.FieldU16("subsample_count")
d.FieldArray("subsamples", func(d *decode.D) {
@ -1278,7 +1290,8 @@ func init() {
d.FieldRawLen("default_kid", 8*16)
if defaultIsEncrypted != 0 && defaultIVSize == 0 {
d.FieldU8("default_constant_iv_size")
defaultConstantIVSize := d.FieldU8("default_constant_iv_size")
d.FieldRawLen("default_constant_iv", int64(defaultConstantIVSize)*8)
}
if t := ctx.currentTrack(); t != nil {
t.defaultIVSize = int(defaultIVSize)

51
format/mp4/mp4.go
View File

@ -102,8 +102,12 @@ type moof struct {
offset int64
defaultSampleSize int64
defaultSampleDescriptionIndex int
dataOffset int64
samplesSizes []int64
truns []trun
}
type trun struct {
dataOffset int64
samplesSizes []int64
}
type sampleDescription struct {
@ -339,20 +343,39 @@ func mp4Tracks(d *decode.D, ctx *decodeContext) {
}
}
sampleNr := 0
for _, m := range t.moofs {
sampleOffset := m.offset + m.dataOffset
for _, sz := range m.samplesSizes {
dataFormat := trackSDDataFormat
if m.defaultSampleDescriptionIndex != 0 && m.defaultSampleDescriptionIndex-1 < len(t.sampleDescriptions) {
sd := t.sampleDescriptions[m.defaultSampleDescriptionIndex-1]
dataFormat = sd.dataFormat
if sd.originalFormat != "" {
dataFormat = sd.originalFormat
}
}
for _, trun := range m.truns {
sampleOffset := m.offset + trun.dataOffset
decodeSampleRange(d, t, dataFormat, "sample", sampleOffset*8, sz*8, t.formatInArg)
sampleOffset += sz
for _, sz := range trun.samplesSizes {
dataFormat := trackSDDataFormat
if m.defaultSampleDescriptionIndex != 0 && m.defaultSampleDescriptionIndex-1 < len(t.sampleDescriptions) {
sd := t.sampleDescriptions[m.defaultSampleDescriptionIndex-1]
dataFormat = sd.dataFormat
if sd.originalFormat != "" {
dataFormat = sd.originalFormat
}
}
// logStrFn := func() string {
// return fmt.Sprintf("%d: %s: %d: (%s): sz=%d %d+%d=%d",
// t.id,
// dataFormat,
// sampleNr,
// trackSDDataFormat,
// sz,
// m.offset,
// m.dataOffset,
// sampleOffset,
// )
// }
// log.Println(logStrFn())
decodeSampleRange(d, t, dataFormat, "sample", sampleOffset*8, sz*8, t.formatInArg)
sampleOffset += sz
sampleNr++
}
}
}
})