snapshot of https://github.com/pion/webrtc.git (main, 2026-09-15; blobs > 131072B omitted)

pkg/media/h265writer/h265writer.go

@@ -0,0 +1,159 @@
+// SPDX-FileCopyrightText: 2026 The Pion community <https://pion.ly>
+// SPDX-License-Identifier: MIT
+
+// Package h265writer implements H265/HEVC media container writer
+package h265writer
+
+import (
+	"bytes"
+	"encoding/binary"
+	"io"
+	"os"
+
+	"github.com/pion/rtp"
+	"github.com/pion/rtp/codecs"
+	"github.com/pion/webrtc/v4/pkg/media/h265reader"
+)
+
+const (
+	typeAP = 48 // Aggregation Packet
+	typeFU = 49 // Fragmentation Unit
+)
+
+// H265Writer is used to take H.265/HEVC RTP packets defined in RFC 7798, parse them and
+// write the data to an io.Writer.
+type H265Writer struct {
+	writer       io.Writer
+	hasKeyFrame  bool
+	cachedPacket *codecs.H265Depacketizer
+}
+
+// New builds a new H265 writer.
+func New(filename string) (*H265Writer, error) {
+	f, err := os.Create(filename) //nolint:gosec
+	if err != nil {
+		return nil, err
+	}
+
+	return NewWith(f), nil
+}
+
+// NewWith initializes a new H265 writer with an io.Writer output.
+func NewWith(w io.Writer) *H265Writer {
+	return &H265Writer{
+		writer: w,
+	}
+}
+
+// WriteRTP adds a new packet and writes the appropriate headers for it.
+func (h *H265Writer) WriteRTP(packet *rtp.Packet) error {
+	if len(packet.Payload) == 0 {
+		return nil
+	}
+
+	if !h.hasKeyFrame {
+		if h.hasKeyFrame = isKeyFrame(packet.Payload); !h.hasKeyFrame {
+			// key frame not defined yet. discarding packet
+			return nil
+		}
+	}
+
+	if h.cachedPacket == nil {
+		h.cachedPacket = &codecs.H265Depacketizer{}
+	}
+
+	data, err := h.cachedPacket.Unmarshal(packet.Payload)
+	if err != nil || len(data) == 0 {
+		return err
+	}
+
+	_, err = h.writer.Write(data)
+
+	return err
+}
+
+// Close closes the underlying writer.
+func (h *H265Writer) Close() error {
+	h.cachedPacket = nil
+	if h.writer != nil {
+		if closer, ok := h.writer.(io.Closer); ok {
+			return closer.Close()
+		}
+	}
+
+	return nil
+}
+
+func isKeyFrame(data []byte) bool {
+	if len(data) < 2 {
+		return false
+	}
+
+	// Get NAL unit type from first byte (bits 6-1)
+	naluType := (data[0] & 0x7E) >> 1
+	if isKeyFrameNalu(h265reader.NalUnitType(naluType)) {
+		return true
+	}
+
+	// Check for parameter sets or IDR frames
+	switch naluType {
+	case typeAP:
+		// For aggregation packets, check if any contained NAL is a key frame
+		return checkAggregationPacketForKeyFrame(data)
+	case typeFU:
+		// For fragmentation units, check the NAL type in the FU header
+		if len(data) < 3 {
+			return false
+		}
+		fuNaluType := h265reader.NalUnitType((data[2] & 0x7E) >> 1)
+
+		return isKeyFrameNalu(fuNaluType)
+	}
+
+	return false
+}
+
+func checkAggregationPacketForKeyFrame(data []byte) bool {
+	// Skip the payload header (2 bytes for H.265)
+	offset := 2
+
+	for offset < len(data) {
+		if offset+2 > len(data) {
+			break
+		}
+
+		// Read NAL unit size (2 bytes in network byte order)
+		var naluSize uint16
+		buf := bytes.NewReader(data[offset : offset+2])
+		if err := binary.Read(buf, binary.BigEndian, &naluSize); err != nil {
+			break
+		}
+		offset += 2
+
+		if offset+int(naluSize) > len(data) {
+			break
+		}
+
+		if naluSize > 0 {
+			// Check NAL unit type
+			naluType := h265reader.NalUnitType((data[offset] & 0x7E) >> 1)
+			if isKeyFrameNalu(naluType) {
+				return true
+			}
+		}
+
+		offset += int(naluSize)
+	}
+
+	return false
+}
+
+func isKeyFrameNalu(naluType h265reader.NalUnitType) bool {
+	switch naluType {
+	case h265reader.NalUnitTypeVps, h265reader.NalUnitTypeSps, h265reader.NalUnitTypePps,
+		h265reader.NalUnitTypeIdrWRadl, h265reader.NalUnitTypeIdrNLp:
+		return true
+	default:
+		return false
+	}
+}