[英]Decoding an RTP stream with H264 data on Android Using MediaCodec
我目前正在嘗試從 RTP 流中解析 H264 數據,然后將其發送到 MediaCodec 以在 Android 的 SurfaceView 上呈現。
但是,我不確定如何:
我還沒有看到任何以清晰簡潔的方式實現的示例,我也沒有發現 MediaCodec 文檔有任何幫助。
任何人在這個領域有任何經驗嗎?
void videoCodec(ByteBuffer input, int flags) {
bufferInfo.set(0, 0, 0, flags);
int inputBufferId = codec.dequeueInputBuffer(10000);
if (inputBufferId >= 0) {
//put data
ByteBuffer inputData = inputBuffers[inputBufferId];
inputData.clear();
inputData.put(input);
//queue it up
codec.queueInputBuffer(inputBufferId, 0, input.limit(), 0, flags);
}
int outputBufferId = codec.dequeueOutputBuffer(bufferInfo, 10000);
if (outputBufferId >= 0) {
// outputBuffers[outputBufferId] is ready to be processed or rendered.
Timber.e("Rendering Data with Index of: %s", outputBufferId);
codec.releaseOutputBuffer(outputBufferId, true);
} else if (outputBufferId == MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED) {
outputBuffers = codec.getOutputBuffers();
} else if (outputBufferId == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {
// Subsequent data will conform to new format.
//format = codec.getOutputFormat();
}
}
MediaFormat format = MediaFormat.createVideoFormat(MediaFormat.MIMETYPE_VIDEO_AVC, 1920, 1080);
codec = MediaCodec.createDecoderByType(MediaFormat.MIMETYPE_VIDEO_AVC);
codec.configure(format, surfaceVideo.getHolder().getSurface(), null, 0);
codec.start();
inputBuffers = codec.getInputBuffers();
outputBuffers = codec.getOutputBuffers();
while (streaming) {
//receive RTP Packet
h264Parser(rtpPacket.getPayload());
}
h264Parser 看起來像這樣:
void h264Parser(byte[] payload) {
int packetType = (byte) payload[0] & (byte) 0x1F;
boolean startBit = (payload[1] & 0x80) != 0;
boolean endBit = (payload[1] & 0x40) != 0;
int flags = 0;
switch (packetType) {
case 7:
pps = new ByteArrayOutputStream();
pps.write(prefix);
pps.write(payload);
break;
case 8:
if (pps.size() > 0) {
pps.write(payload);
hasPps = true;
flags = MediaCodec.BUFFER_FLAG_CODEC_CONFIG;
payload = pps.toByteArray();
//Send packet to decoder
videoCodec(ByteBuffer.wrap(payload), flags);
break;
case 28:
if (hasPps) {
if (startBit) {
baos = new ByteArrayOutputStream();
baos.write(prefix);
baos.write(payload);
} else if (endBit) {
if(baos != null) {
baos.write(payload);
flags = MediaCodec.BUFFER_FLAG_KEY_FRAME;
payload = baos.toByteArray();
//Send packet to decoder
videoCodec(ByteBuffer.wrap(payload), flags);
hasPps = false;
} else {
if(baos != null ) {
baos.write(payload);
}
}
}
break;
case 1:
break;
default:
}
據我所知 MediaCodec 使用完整的訪問單元,而不僅僅是切片(有人糾正我我錯了)
因此,您必須構建一個完整的 RTP 訪問單元並將其提供給解碼器(遺憾的是我沒有 RTP 經驗,無法幫助您構建一個)。
您將訪問單元發送到解碼器,如下所示:
出列輸入緩沖區
int inputBufferIndex = decoder.dequeueInputBuffer(TIMEOUT_USEC); ByteBuffer inputBuffer = videoDecoderInputBuffers[videoInputBufIndex];
填寫您的訪問單元
inputBuffer.put(acessUnit); inputBuffer.flip();
將緩沖區排隊以進行解碼
decoder.queueInputBuffer(inputBufferIndex,0,inputBuffer.limit(), 0, FLAGS);
希望這會有幫助
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