av/container/mts/mpegts_test.go

131 lines
2.7 KiB
Go

package mts
import (
"bytes"
"math/rand"
"testing"
"time"
"bitbucket.org/ausocean/av/container/mts/pes"
"bitbucket.org/ausocean/av/container/mts/psi"
)
// TestGetPTSRange checks that GetPTSRange can correctly get the first and last
// PTS in an MPEGTS clip.
func TestGetPTSRange(t *testing.T) {
const (
numOfFrames = 20
maxFrameSize = 1000
minFrameSize = 100
rate = 25 // fps
interval = float64(1) / rate // s
ptsFreq = 90000 // Hz
)
// Generate randomly sized data for each frame.
rand.Seed(time.Now().UnixNano())
frames := make([][]byte, numOfFrames)
for i := range frames {
size := rand.Intn(maxFrameSize-minFrameSize) + minFrameSize
frames[i] = make([]byte, size)
}
var clip bytes.Buffer
// Write the PSI first.
err := writePSI(clip)
if err != nil {
t.Fatalf("did not expect error writing psi: %v", err)
}
// Now write frames.
var curTime float64
for _, frame := range frames {
nextPTS := curTime * ptsFreq
err = writeFrame(clip, frame, uint64(nextPTS))
if err != nil {
t.Fatalf("did not expect error writing frame: %v", err)
}
curTime += interval
}
got, err := GetPTSRange(clip.Bytes())
if err != nil {
t.Fatalf("did not expect error getting PTS range: %v", err)
}
want := [2]uint64{0, uint64((numOfFrames - 1) * interval * ptsFreq)}
if got != want {
t.Errorf("did not get expected result.\n Got: %v\n Want: %v\n", got, want)
}
}
// writePSI is a helper function write the PSI found at the start of a clip.
func writePSI(b bytes.Buffer) error {
// Write PAT.
pat := Packet{
PUSI: true,
PID: PatPid,
CC: 0,
AFC: HasPayload,
Payload: psi.AddPadding(patTable),
}
_, err := b.Write(pat.Bytes(nil))
if err != nil {
return err
}
// Write PMT.
pmt := Packet{
PUSI: true,
PID: PmtPid,
CC: 0,
AFC: HasPayload,
Payload: psi.AddPadding(pmtTable),
}
_, err = b.Write(pmt.Bytes(nil))
if err != nil {
return err
}
return nil
}
// writeFrame is a helper function used to form a PES packet from a frame, and
// then fragment this across MPEGTS packets where they are then written to the
// given buffer.
func writeFrame(b bytes.Buffer, frame []byte, pts uint64) error {
// Prepare PES data.
pesPkt := pes.Packet{
StreamID: videoStreamID,
PDI: hasPTS,
PTS: pts,
Data: frame,
HeaderLength: 5,
}
buf := pesPkt.Bytes(nil)
// Write PES data acroos MPEGTS packets.
pusi := true
for len(buf) != 0 {
pkt := Packet{
PUSI: pusi,
PID: videoPid,
RAI: pusi,
CC: 0,
AFC: hasAdaptationField | hasPayload,
PCRF: pusi,
}
n := pkt.FillPayload(buf)
buf = buf[n:]
pusi = false
_, err := b.Write(pkt.Bytes(nil))
if err != nil {
return err
}
}
return nil
}