初始提交：短剧库源码（含转码优化 ultrafast）

2026-09-17 19:09:08 +08:00
commit 07dc0f1059
247 changed files with 43242 additions and 0 deletions
@@ -0,0 +1,201 @@
+package app
+
+import (
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"io"
+	"strings"
+)
+
+type playbackRemuxKey struct{}
+
+type playbackMP4Box struct {
+	kind string
+	body []byte
+}
+
+const playbackInitLimit = 256 * 1024
+
+func readPlaybackMP4Init(reader io.Reader) ([]byte, string, error) {
+	var initial []byte
+	for len(initial) < playbackInitLimit {
+		header := make([]byte, 8)
+		if _, err := io.ReadFull(reader, header); err != nil {
+			return nil, "", err
+		}
+		size := uint64(binary.BigEndian.Uint32(header))
+		kind := string(header[4:8])
+		if size == 1 {
+			extended := make([]byte, 8)
+			if _, err := io.ReadFull(reader, extended); err != nil {
+				return nil, "", err
+			}
+			size = binary.BigEndian.Uint64(extended)
+			header = append(header, extended...)
+		}
+		if size < uint64(len(header)) || size > uint64(playbackInitLimit-len(initial)) || kind != "ftyp" && kind != "free" && kind != "moov" {
+			return nil, "", errors.New("播放初始化数据无效或过大")
+		}
+		body := make([]byte, int(size)-len(header))
+		if _, err := io.ReadFull(reader, body); err != nil {
+			return nil, "", err
+		}
+		initial = append(initial, header...)
+		initial = append(initial, body...)
+		if kind == "moov" {
+			return initial, playbackRemuxMIME(body), nil
+		}
+	}
+	return nil, "", errors.New("播放初始化数据过大")
+}
+
+func playbackMP4Boxes(data []byte) ([]playbackMP4Box, bool) {
+	var boxes []playbackMP4Box
+	for len(data) > 0 {
+		if len(data) < 8 {
+			return nil, false
+		}
+		size, header := uint64(binary.BigEndian.Uint32(data)), 8
+		if size == 1 {
+			if len(data) < 16 {
+				return nil, false
+			}
+			size, header = binary.BigEndian.Uint64(data[8:16]), 16
+		}
+		if size < uint64(header) || size > uint64(len(data)) {
+			return nil, false
+		}
+		boxes = append(boxes, playbackMP4Box{kind: string(data[4:8]), body: data[header:int(size)]})
+		data = data[int(size):]
+	}
+	return boxes, true
+}
+
+func playbackMP4Child(data []byte, path ...string) []byte {
+	for _, kind := range path {
+		boxes, valid := playbackMP4Boxes(data)
+		if !valid {
+			return nil
+		}
+		data = nil
+		for _, box := range boxes {
+			if box.kind == kind {
+				if data != nil {
+					return nil
+				}
+				data = box.body
+			}
+		}
+		if data == nil {
+			return nil
+		}
+	}
+	return data
+}
+
+func playbackRemuxMIME(moov []byte) string {
+	boxes, valid := playbackMP4Boxes(moov)
+	if !valid {
+		return ""
+	}
+	var video string
+	audio := false
+	for _, track := range boxes {
+		if track.kind != "trak" {
+			continue
+		}
+		stsd := playbackMP4Child(track.body, "mdia", "minf", "stbl", "stsd")
+		if len(stsd) < 8 || binary.BigEndian.Uint32(stsd[4:8]) != 1 {
+			return ""
+		}
+		entries, valid := playbackMP4Boxes(stsd[8:])
+		if !valid || len(entries) != 1 {
+			return ""
+		}
+		entry := entries[0]
+		switch entry.kind {
+		case "avc1":
+			if video != "" || len(entry.body) < 78 {
+				return ""
+			}
+			width, height := int(binary.BigEndian.Uint16(entry.body[24:26])), int(binary.BigEndian.Uint16(entry.body[26:28]))
+			if width == 0 || height == 0 || width > 1920 || height > 1920 || width*height > 1920*1080 {
+				return ""
+			}
+			avcc := playbackMP4Child(entry.body[78:], "avcC")
+			if len(avcc) < 7 || avcc[0] != 1 || avcc[1] != 66 && avcc[1] != 77 && avcc[1] != 100 || avcc[3] == 0 || avcc[3] > 42 {
+				return ""
+			}
+			video = fmt.Sprintf("avc1.%02X%02X%02X", avcc[1], avcc[2], avcc[3])
+		case "mp4a":
+			if audio || len(entry.body) < 28 || binary.BigEndian.Uint16(entry.body[8:10]) != 0 {
+				return ""
+			}
+			channels := binary.BigEndian.Uint16(entry.body[16:18])
+			if channels < 1 || channels > 2 || !playbackAACLC(playbackMP4Child(entry.body[28:], "esds")) {
+				return ""
+			}
+			audio = true
+		default:
+			return ""
+		}
+	}
+	if video == "" {
+		return ""
+	}
+	codecs := []string{video}
+	if audio {
+		codecs = append(codecs, "mp4a.40.2")
+	}
+	return `video/mp4; codecs="` + strings.Join(codecs, ", ") + `"`
+}
+
+func playbackMP4Descriptor(data []byte, tag byte) []byte {
+	if len(data) < 2 || data[0] != tag {
+		return nil
+	}
+	length := 0
+	for i := 1; i < len(data) && i <= 4; i++ {
+		length = length<<7 | int(data[i]&0x7f)
+		if data[i]&0x80 == 0 {
+			if length > len(data)-i-1 {
+				return nil
+			}
+			return data[i+1 : i+1+length]
+		}
+	}
+	return nil
+}
+
+func playbackAACLC(esds []byte) bool {
+	if len(esds) < 4 {
+		return false
+	}
+	es := playbackMP4Descriptor(esds[4:], 3)
+	if len(es) < 3 {
+		return false
+	}
+	flags, offset := es[2], 3
+	if flags&0x80 != 0 {
+		offset += 2
+	}
+	if flags&0x40 != 0 {
+		if offset >= len(es) {
+			return false
+		}
+		offset += 1 + int(es[offset])
+	}
+	if flags&0x20 != 0 {
+		offset += 2
+	}
+	if offset >= len(es) {
+		return false
+	}
+	decoder := playbackMP4Descriptor(es[offset:], 4)
+	if len(decoder) < 13 || decoder[0] != 0x40 || decoder[1]>>2 != 5 {
+		return false
+	}
+	config := playbackMP4Descriptor(decoder[13:], 5)
+	return len(config) >= 2 && config[0]>>3 == 2
+}