我正在从服务器传输H264 NAL，将它们包装为FLV标记，并将它们传递到带有appendBytes（数据生成模式）的NetStream中。但是，当视频正常播放时，流会延迟大约一秒钟。
我已经尝试过设置bufferTime，bufferTimeMax但没有运气来阻止缓冲进行。
我也尝试过使用RESET_SEEK和END_SEQUENCE的NetStream.seek（）和NetStream.appendBytesAction（）的各种组合，再次无济于事。
这里有一个我不知道的伎俩，有没有办法防止这种延迟？
有趣的是，我没有看到我传入的音频延迟（PCMU）所以我最终会出现唇形同步问题。
更新：仍然卡住了，所以发布我正在使用的代码：
var timestamp : uint = networkPayload.readUnsignedInt();
if (videoTimestampBase == 0) {
videoTimestampBase = timestamp;
}
timestamp = timestamp - videoTimestampBase;
timestamp = timestamp / 90.0;
// skip 7 bytes of marker
networkPayload.position = 7;
var nalType : int = networkPayload.readByte();
nalType &= 0x1F;
networkPayload.position = 7;
// reformat Annex B bitstream encoding, to Mp4 - remove timestamp and bitstream marker (3 bytes)
var mp4Payload : ByteArray = new ByteArray();
var mp4PayloadLength : int = networkPayload.bytesAvailable;
mp4Payload.writeUnsignedInt(mp4PayloadLength);
mp4Payload.writeBytes(networkPayload, 7, mp4PayloadLength);
mp4Payload.position = 0;
if (nalType == 8) {
// PPS
ppsNAL = new ByteArray();
// special case for PPS/SPS - don't length encode
ppsLength = mp4Payload.bytesAvailable - 4;
ppsNAL.writeBytes(mp4Payload, 4, mp4Payload.bytesAvailable - 4);
if (spsNAL == null) {
return;
}
} else if (nalType == 7) {
// SPS
spsNAL = new ByteArray();
// special case for PPS/SPS - don't length encode
spsLength = mp4Payload.bytesAvailable - 4;
spsNAL.writeBytes(mp4Payload, 4, mp4Payload.bytesAvailable - 4);
if (ppsNAL == null) {
return;
}
}
if ((spsNAL != null) && (ppsNAL != null)) {
Log.debug(TAG, "Writing sequence header: " + spsLength + "," + ppsLength + "," + timestamp);
var sequenceHeaderTag : FLVTagVideo = new FLVTagVideo();
sequenceHeaderTag.codecID = FLVTagVideo.CODEC_ID_AVC;
sequenceHeaderTag.frameType = FLVTagVideo.FRAME_TYPE_KEYFRAME;
sequenceHeaderTag.timestamp = timestamp;
sequenceHeaderTag.avcPacketType = FLVTagVideo.AVC_PACKET_TYPE_SEQUENCE_HEADER;
spsNAL.position = 1;
var profile : int = spsNAL.readByte();
var compatibility : int = spsNAL.readByte();
var level : int = spsNAL.readByte();
Log.debug(TAG, profile + "," + compatibility + "," + level + "," + spsLength);
var avcc : ByteArray = new ByteArray();
avcc.writeByte(0x01); // avcC version 1
// profile, compatibility, level
avcc.writeByte(profile);
avcc.writeByte(compatibility);
avcc.writeByte(0x20); //level);
avcc.writeByte(0xff); // 111111 + 2 bit NAL size - 1
avcc.writeByte(0xe1); // number of SPS
avcc.writeByte(spsLength >> 8); // 16-bit SPS byte count
avcc.writeByte(spsLength);
avcc.writeBytes(spsNAL, 0, spsLength); // the SPS
avcc.writeByte(0x01); // number of PPS
avcc.writeByte(ppsLength >> 8); // 16-bit PPS byte count
avcc.writeByte(ppsLength);
avcc.writeBytes(ppsNAL, 0, ppsLength);
sequenceHeaderTag.data = avcc;
// clear the pps/sps til next buffer
var bytes : ByteArray = new ByteArray();
sequenceHeaderTag.write(bytes);
stream.appendBytes(bytes);
ppsNAL = null;
spsNAL = null;
} else {
if ((timestamp != currentTimestamp) || (currentVideoTag == null)) {
if (currentVideoTag != null) {
currentVideoTag.data = currentSegment;
var tagData : ByteArray = new ByteArray();
currentVideoTag.write(tagData);
stream.appendBytes(tagData);
}
currentVideoTag = new FLVTagVideo();
currentVideoTag.codecID = FLVTagVideo.CODEC_ID_AVC;
currentVideoTag.frameType = FLVTagVideo.FRAME_TYPE_INTER;
if (nalType == 5) {
currentVideoTag.frameType = FLVTagVideo.FRAME_TYPE_KEYFRAME;
}
lastNalType = nalType;
currentVideoTag.avcPacketType = FLVTagVideo.AVC_PACKET_TYPE_NALU;
currentVideoTag.timestamp = timestamp;
currentVideoTag.avcCompositionTimeOffset = 0;
currentSegment = new ByteArray();
currentTimestamp = timestamp;
}
mp4Payload.position = 0;
currentSegment.writeBytes(mp4Payload);
}
更新，更多细节，这是传递的时间戳：
DEBUG: StreamPlayback: 66,-32,20,19
DEBUG: StreamPlayback: Timestamp: 0
DEBUG: StreamPlayback: Timestamp: 63
DEBUG: StreamPlayback: stream status update: netStatus NetStream.Buffer.Full
DEBUG: StreamPlayback: Timestamp: 137
DEBUG: StreamPlayback: Timestamp: 200
DEBUG: StreamPlayback: Timestamp: 264
DEBUG: StreamPlayback: Timestamp: 328
DEBUG: StreamPlayback: Timestamp: 403
DEBUG: StreamPlayback: Timestamp: 467
DEBUG: StreamPlayback: Timestamp: 531
DEBUG: StreamPlayback: Timestamp: 595
DEBUG: StreamPlayback: Timestamp: 659
DEBUG: StreamPlayback: Timestamp: 723
DEBUG: StreamPlayback: Timestamp: 830
DEBUG: StreamPlayback: Timestamp: 894
DEBUG: StreamPlayback: Timestamp: 958
DEBUG: StreamPlayback: Timestamp: 1021
DEBUG: StreamPlayback: Timestamp: 1086
DEBUG: StreamPlayback: Timestamp: 1161
DEBUG: StreamPlayback: Timestamp: 1225
DEBUG: StreamPlayback: Timestamp: 1289
DEBUG: StreamPlayback: Timestamp: 1353
DEBUG: StreamPlayback: Timestamp: 1418
DEBUG: StreamPlayback: Timestamp: 1491
DEBUG: StreamPlayback: Timestamp: 1556
DEBUG: StreamPlayback: Timestamp: 1633
DEBUG: StreamPlayback: Timestamp: 1684
DEBUG: StreamPlayback: Timestamp: 1747
DEBUG: StreamPlayback: stream status update: netStatus NetStream.Video.DimensionChange
DEBUG: StreamPlayback: Timestamp: 1811
干杯，
千电子伏
答案 0 :(得分：0)
解决方案一：
媒体实际上并没有开始播放 触发NetStream.Video.DimensionChange
为什么不在开始任何追加之前暂停 NetStream？然后添加标签，直到NetStream确认“尺寸更改”。在Net Status处理程序中，然后取消暂停 NetStream 希望它会播放同步，因为在暂停模式下，声音或视频的播放头都没有移动。
stream.addEventListener(NetStatusEvent.NET_STATUS, stream_StatusHandler);
stream.play(null);
stream.appendBytesAction(NetStreamAppendBytesAction.RESET_BEGIN);
stream.pause(); //# pause before beginning FLV A/V Tag appends
public function stream_StatusHandler (evt:NetStatusEvent) : void
{
trace("DEBUG: StreamPlayback : NEW evt.info.code : " + evt.info.code );
switch (evt.info.code)
{
//# in case its "NetStream.Buffer.Full"
case "NetStream.Buffer.Full" :
trace("DEBUG: StreamPlayback : NetStream.Buffer.Full...");
break;
//# in case its "NetStream.Video.DimensionChange" :
case "NetStream.Video.DimensionChange" :
trace("DEBUG: StreamPlayback : #### Video Dimensions have changed...");
trace("DEBUG: StreamPlayback : #### NEW Detected video.videoHeight : " + video.videoHeight );
stream.resume(); //# resume playback
//# or use : stream.togglePause();
break;
}
}
如果这不起作用，那么你可以试试......
解决方案二：
我不知道如何更快地发生尺寸变化事件 虽然......有没有办法伪造它？
使用位图数据创建仅由简单颜色块组成的动态视频帧。该块与您的视频流的分辨率大小不同。您首先附加块，与您自己的视频帧的差异将触发尺寸更改。
注意：如果您的视频触发太晚（即：A / V未同步，则表示您首先发送的音频标签过多（可能是视频时间后的错误时间戳？）...尝试检查时间戳。音频总是在视频之前，不得超过相关视频标签的时间戳。）
下面的示例代码生成 100宽x 50高视频帧（位图数据被编码为屏幕 - 视频格式并附加为视频标签）。
// 1) ## Setup Video Object + Append FLV header + Append Metadata etc
// 2) ## Run function below before appending your first Video tag...
force_Dimension_Adjust();
// 3) ## Do your usual appends...
以下是相关代码：force_Dimension_Adjust();
public var BA_BMD_Frame : ByteArray;
public var BA_Temp : ByteArray;
public function force_Dimension_Adjust() : void
{
trace("DEBUG: #### doing function : force_Dimension_Adjust");
//create BMD frame for dimension change
generate_Frame_BMPdata(); //# Puts result video tag into BA_BMD_Frame
BA_BMD_Frame.position = 0;
stream.appendBytes( BA_BMD_Frame ); //should trigger "dimesion change" for video picture size
trace("DEBUG: StreamPlayback : #### APPENDED :::: BA_BMD_Frame : " );
}
public function generate_Frame_BMPdata() : void
{
//## Simple colour block as video frame content
//## (pW = Picture Width, pH = Picture Height)
var pW : int = 100; var pH : int = 50;
var temp_BMD = new BitmapData(pW, pH, false, 0x5500AA ); //R-G-B 5500AA = purple
var temp_BMP = new Bitmap(temp_BMD);
// 1) #### encode BitmapData to codec Screen Video
BA_BMD_Frame.clear(); BA_Temp.clear(); BA_Temp.position = 0; //# Resets
encode_SCREENVIDEO (BA_Temp, temp_BMD); //# Put encoded BMD into a temp ByteArray
// 2) #### Create Video Frame TAG to hold encoded frame
BA_BMD_Frame.writeByte(0x09); //# is video TAG
writeUInt24( BA_BMD_Frame, BA_Temp.length ); //# Write 3 bytes : size of BMD bytes length
BA_BMD_Frame.writeUnsignedInt(0x00); //# Write 4 byte timestamp : 0x00 0x00 0x00 0x00
writeUInt24( BA_BMD_Frame, 0x00 ); //# Write 3 bytes (stream ID etc) : 0x00 0x00 0x00
BA_BMD_Frame.position = BA_BMD_Frame.length;
BA_BMD_Frame.writeBytes( BA_Temp ); //# Write encoded BMD bytes here
BA_BMD_Frame.position = BA_BMD_Frame.length;
BA_BMD_Frame.writeUnsignedInt( BA_BMD_Frame.length - 4 ); //# Close : total size of this byteArray (TAG) length minus 4
BA_BMD_Frame.position = 0; //# Reset position
}
public function encode_SCREENVIDEO ( input_BA : ByteArray , input_BMD : BitmapData ) : void //ByteArray
{
var w:int = input_BMD.width; var h:int = input_BMD.height;
//# Video Type = 1 (Keyframe) |&&| Codec ID = 3 (Screen-Video)
input_BA.writeByte(0x13);
//# SCREENVIDEOPACKET 'header'
writeUI4_12( input_BA, int( (BLOCK_WIDTH /16) - 1 ), w ); //12 bits for width
writeUI4_12( input_BA, int( (BLOCK_HEIGHT /16) - 1 ), h ); //12 bits for height
//# Create IMAGEBLOCKS
const BLOCK_WIDTH:int = input_BMD.width; //# is 100;
const BLOCK_HEIGHT:int = input_BMD.height; //# is 50;
var rowMax:int = int(h / BLOCK_HEIGHT);
var rowRemainder:int = h % BLOCK_HEIGHT;
if (rowRemainder > 0) rowMax += 1;
var colMax:int = int(w / BLOCK_WIDTH);
var colRemainder:int = w % BLOCK_WIDTH;
if (colRemainder > 0) colMax += 1;
var block:ByteArray = new ByteArray();
block.endian = Endian.LITTLE_ENDIAN;
for (var row:int = 0; row < rowMax; row++)
{
for (var col:int = 0; col < colMax; col++)
{
var xStart:uint = col * BLOCK_WIDTH;
var xLimit:int = (colRemainder > 0 && col + 1 == colMax) ? colRemainder : BLOCK_WIDTH;
var xEnd:int = xStart + xLimit;
var yStart:uint = h - (row * BLOCK_HEIGHT); //# Read BMP Data from bottom to top
var yLimit:int = (rowRemainder > 0 && row + 1 == rowMax) ? rowRemainder : BLOCK_HEIGHT;
var yEnd:int = yStart - yLimit;
block.clear(); //# re-use ByteArray
for (var y:int = yStart-1; y >= yEnd; y--) //# FLV stores Bitmap Data from bottom to top)
{
for (var x:int = xStart; x < xEnd; x++)
{
var p:uint = input_BMD.getPixel(x, y);
writeUInt24( block, p ); //# write B-G-R pixel values
}
}
block.compress();
input_BA.writeShort(block.length); // write block length (2 bytes == 16 bits)
input_BA.writeBytes( block ); // write block
}
}
block.length = 0; block = null;
input_BA.position = input_BA.length;
}
//// Supporting functions
public function writeUInt24( input_BA:ByteArray, val:uint ) : void
{
input_BA.position = input_BA.position;
temp_Int_1 = val >> 16;
temp_Int_2 = val >> 8 & 0xff;
temp_Int_3 = val & 0xff;
input_BA.writeByte(temp_Int_1); input_BA.writeByte(temp_Int_2);
input_BA.writeByte(temp_Int_3);
}
public function writeUI4_12(input_BA:ByteArray, p1:uint, p2:uint):void
{
// writes a 4-bit value followed by a 12-bit value in a total of 16 bits (2 bytes)
var byte1a:int = p1 << 4;
var byte1b:int = p2 >> 8;
var byte1:int = byte1a + byte1b;
var byte2:int = p2 & 0xff;
input_BA.writeByte(byte1); input_BA.writeByte(byte2);
}