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avi: Handle stream sample size #776

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merged 1 commit into from
Oct 7, 2023
Merged

avi: Handle stream sample size #776

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28 changes: 22 additions & 6 deletions format/riff/avi.go
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Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
package riff

// TODO:
// mp3 mappig, seem there can be many frames in one sample and they span samples?
// mp3 mappig, samples can span?
// hevc mapping?
// DV handler https://learn.microsoft.com/en-us/windows/win32/directshow/dv-data-in-the-avi-file-format
// palette change
Expand Down Expand Up @@ -120,6 +120,7 @@ type aviStream struct {
hasFormat bool
format *decode.Group
formatInArg any
sampleSize uint64
indexes []ranges.Range
ixSamples []ranges.Range
}
Expand Down Expand Up @@ -327,7 +328,7 @@ func aviDecode(d *decode.D) any {
d.FieldU32("length")
d.FieldU32("suggested_buffer_size")
d.FieldU32("quality")
d.FieldU32("sample_size")
sampleSize := d.FieldU32("sample_size")
d.FieldStruct("frame", func(d *decode.D) {
d.FieldU16("left")
d.FieldU16("top")
Expand All @@ -338,6 +339,7 @@ func aviDecode(d *decode.D) any {
if stream, ok := path.topData().(*aviStream); ok {
stream.typ = typ
stream.handler = handler
stream.sampleSize = sampleSize
}

return false, nil
Expand Down Expand Up @@ -557,14 +559,28 @@ func aviDecode(d *decode.D) any {
})
}

// TODO: handle zero length samples differently?
// TODO: palette change
decodeSample := func(d *decode.D, sr ranges.Range) {
d.RangeFn(sr.Start, sr.Len, func(d *decode.D) {
if sr.Len > 0 && ai.DecodeSamples && stream.hasFormat {
d.FieldFormat("sample", stream.format, stream.formatInArg)
} else {
if sr.Len == 0 {
d.FieldRawLen("sample", d.BitsLeft())
return
}

subSampleSize := int64(stream.sampleSize) * 8
// TODO: <= 4*8 heuristics to not create separate pcm samples
if subSampleSize == 0 || subSampleSize <= 4*8 {
subSampleSize = sr.Len
}

for d.BitsLeft() > 0 {
d.FramedFn(subSampleSize, func(d *decode.D) {
if ai.DecodeSamples && stream.hasFormat {
d.FieldFormat("sample", stream.format, stream.formatInArg)
} else {
d.FieldRawLen("sample", d.BitsLeft())
}
})
}
})
}
Expand Down