refactor: make toplevel makefile work

cmd/mp4ff-crop/main.go

@@ -11,6 +11,7 @@ import (
 	"io"
 	"log"
 	"os"
+	"sort"
 	"strings"
 
 	"github.com/Eyevinn/mp4ff/mp4"
@@ -387,3 +388,147 @@ func minUint32(a, b uint32) uint32 {
 	}
 	return b
 }
+
+func cropStblChildren(traks []*mp4.TrakBox, trakOuts map[uint32]*trakOut) (err error) {
+	for _, trak := range traks {
+		trakID := trak.Tkhd.TrackID
+		stbl := trak.Mdia.Minf.Stbl
+		to := trakOuts[trakID]
+		for _, ch := range stbl.Children {
+			switch ch.Type() {
+			case "stts":
+				cropStts(ch.(*mp4.SttsBox), to.lastSampleNr)
+			case "stss":
+				cropStss(ch.(*mp4.StssBox), to.lastSampleNr)
+			case "ctts":
+				cropCtts(ch.(*mp4.CttsBox), to.lastSampleNr)
+			case "stsc":
+				err = cropStsc(ch.(*mp4.StscBox), to.lastSampleNr)
+			case "stsz":
+				cropStsz(ch.(*mp4.StszBox), to.lastSampleNr)
+			case "sdtp":
+				cropSdtp(ch.(*mp4.SdtpBox), to.lastSampleNr)
+			case "stco":
+				updateStco(ch.(*mp4.StcoBox), to.chunkOffsets)
+			case "co64":
+				updateCo64(ch.(*mp4.Co64Box), to.chunkOffsets)
+			}
+		}
+	}
+	return err
+}
+
+func cropStts(b *mp4.SttsBox, lastSampleNr uint32) {
+	var countedSamples uint32 = 0
+	lastEntry := -1
+	for i := 0; i < len(b.SampleCount); i++ {
+		if countedSamples < lastSampleNr {
+			lastEntry++
+		}
+		if countedSamples+b.SampleCount[i] >= lastSampleNr {
+			break
+		}
+		countedSamples += b.SampleCount[i]
+	}
+	remaining := lastSampleNr - countedSamples
+	if remaining > 0 {
+		b.SampleCount[lastEntry] = remaining
+	}
+
+	b.SampleCount = b.SampleCount[:lastEntry+1]
+	b.SampleTimeDelta = b.SampleTimeDelta[:lastEntry+1]
+}
+
+func cropStss(b *mp4.StssBox, lastSampleNr uint32) {
+	nrEntries := b.EntryCount()
+	nrEntriesToKeep := 0
+	for i := uint32(0); i < nrEntries; i++ {
+		if b.SampleNumber[i] > lastSampleNr {
+			break
+		}
+		nrEntriesToKeep++
+	}
+	b.SampleNumber = b.SampleNumber[:nrEntriesToKeep]
+}
+
+func cropCtts(b *mp4.CttsBox, lastSampleNr uint32) {
+	lastIdx := sort.Search(len(b.EndSampleNr), func(i int) bool { return b.EndSampleNr[i] >= lastSampleNr })
+	// Finally cut down the endSampleNr for this index
+	b.EndSampleNr[lastIdx] = lastSampleNr
+	b.EndSampleNr = b.EndSampleNr[:lastIdx+1]
+	b.SampleOffset = b.SampleOffset[:lastIdx]
+}
+
+func cropStsc(b *mp4.StscBox, lastSampleNr uint32) error {
+	entryIdx := b.FindEntryNrForSampleNr(lastSampleNr, 0)
+	lastEntry := b.Entries[entryIdx]
+	b.Entries = b.Entries[:entryIdx+1]
+	if len(b.SampleDescriptionID) > 0 {
+		b.Entries = b.Entries[:entryIdx+1]
+	}
+	samplesLeft := lastSampleNr - lastEntry.FirstSampleNr + 1
+	nrChunksInLast := samplesLeft / lastEntry.SamplesPerChunk
+	nrLeft := samplesLeft - nrChunksInLast*lastEntry.SamplesPerChunk
+	if nrLeft > 0 {
+		sdid := b.GetSampleDescriptionID(int(lastEntry.FirstChunk))
+		err := b.AddEntry(lastEntry.FirstChunk+nrChunksInLast, nrLeft, sdid)
+		if err != nil {
+			return fmt.Errorf("stsc AddEntry: %w", err)
+		}
+	}
+	return nil
+}
+
+func cropStsz(b *mp4.StszBox, lastSampleNr uint32) {
+	if b.SampleUniformSize == 0 {
+		b.SampleSize = b.SampleSize[:lastSampleNr]
+	}
+	b.SampleNumber = lastSampleNr
+}
+
+func cropSdtp(b *mp4.SdtpBox, lastSampleNr uint32) {
+	if len(b.Entries) > int(lastSampleNr) {
+		b.Entries = b.Entries[:lastSampleNr]
+	}
+}
+
+func updateStco(b *mp4.StcoBox, offsets []uint64) {
+	b.ChunkOffset = make([]uint32, len(offsets))
+	for i := range offsets {
+		b.ChunkOffset[i] = uint32(offsets[i])
+	}
+}
+
+func updateCo64(b *mp4.Co64Box, offsets []uint64) {
+	b.ChunkOffset = make([]uint64, len(offsets))
+	_ = copy(b.ChunkOffset, offsets)
+}
+
+type byteRange struct {
+	start uint64
+	end   uint64 // Included
+}
+
+type byteRanges struct {
+	ranges []byteRange
+}
+
+func createByteRanges() *byteRanges {
+	return &byteRanges{}
+}
+
+func (b *byteRanges) addRange(start, end uint64) {
+	if len(b.ranges) == 0 || b.ranges[len(b.ranges)-1].end+1 != start {
+		b.ranges = append(b.ranges, byteRange{start, end})
+		return
+	}
+	b.ranges[len(b.ranges)-1].end = end
+}
+
+func (b *byteRanges) size() uint64 {
+	var totSize uint64 = 0
+	for _, br := range b.ranges {
+		totSize += br.end - br.start + 1
+	}
+	return uint64(totSize)
+}