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-rw-r--r--dxr3audiodecoder.c316
1 files changed, 316 insertions, 0 deletions
diff --git a/dxr3audiodecoder.c b/dxr3audiodecoder.c
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+/*
+ * dxr3audiodecoder.c
+ *
+ * Copyright (C) 2002-2004 Kai Möller
+ * Copyright (C) 2004 Christian Gmeiner
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ */
+
+
+/*
+ ToDo:
+ - cDxr3AudioDecoder::Init: Why are we always reinit the codec?
+*/
+
+#include <stdio.h>
+#include "dxr3audiodecoder.h"
+#include "dxr3pesframe.h"
+
+// ==================================
+const int LPCM_HEADER_LENGTH = 7;
+
+// ==================================
+//! constructor
+cDxr3AudioDecoder::cDxr3AudioDecoder() : rbuf(50000), ac3dtsDecoder(&rbuf)
+{
+ decoderOpened = false;
+ audioSynched = false;
+ volume = 255;
+ Codec.id = CODEC_ID_MP2;
+
+ Init();
+
+ lastHeader[0] = 0xFF;
+ lastHeader[1] = lastHeader[2] = lastHeader[3] = 0;
+};
+
+// ==================================
+//! deconst.
+cDxr3AudioDecoder::~cDxr3AudioDecoder()
+{
+ // close codec, if it is open
+ cDxr3Ffmepg::Instance().CloseCodec(Codec);
+};
+
+// ==================================
+//! (re)init ffmpeg codec
+void cDxr3AudioDecoder::Init()
+{
+ // (re)init codec
+ cDxr3Ffmepg::Instance().CloseCodec(Codec);
+ if (cDxr3Ffmepg::Instance().FindCodec(Codec))
+ {
+ cDxr3Ffmepg::Instance().OpenCodec(Codec);
+ rate = channels = -1;
+ frameSize = Codec.codec_context.frame_size;
+ decoderOpened = true;
+ foundHeader = false;
+ decodeAudio = true;
+
+ //lastHeader[0] = 0xFF;
+ //lastHeader[1] = lastHeader[2] = lastHeader[3] = 0;
+ }
+ else
+ {
+ decoderOpened = false;
+ }
+}
+
+// ==================================
+//! decode given buffer
+void cDxr3AudioDecoder::Decode(const uint8_t* buf, int length, uint32_t pts,
+ cDxr3SyncBuffer &aBuf)
+{
+ if (!decoderOpened)
+ {
+ // No decoder is open, so it
+ // is better to stop here.
+ return;
+ }
+
+ int len;
+ int out_size;
+
+ enum audioException
+ {
+ WRONG_LENGTH,
+ UNEXPECTED_PARAMETER_CHANGE
+ };
+
+ int i = 0;
+ for (i = 0; i < length-4 && !foundHeader; i++)
+ {
+ unsigned int tempHead = *((unsigned int*)(buf+i));
+ if (HeadCheck(tempHead))
+ {
+ if ((buf[i+2] & 0xFC) != (lastHeader[2] & 0xFC))
+ {
+ dsyslog("dxr3: audiodecoder: found different audio header"
+ " (new: %#x, old: %#x), (re)initializing",
+ *((uint32_t*) lastHeader), *((uint32_t*) (buf+i)));
+
+ Init();
+ lastHeader[0] = buf[i];
+ lastHeader[1] = buf[i+1];
+ lastHeader[2] = buf[i+2];
+ lastHeader[3] = buf[i+3];
+ }
+ foundHeader = true;
+ }
+ }
+
+ if (audioSynched)
+ {
+ // no header found
+ decodeAudio = true;
+ }
+ else
+ {
+ if (foundHeader && pts)
+ {
+ decodeAudio = true;
+ audioSynched = true;
+ }
+ }
+
+ try
+ {
+ while (length > 0 && decodeAudio)
+ {
+ len = avcodec_decode_audio(&Codec.codec_context,
+ (short *)(&pcmbuf), &out_size,
+ const_cast<uint8_t *>(buf), length);
+ if (len < 0 || out_size < 0)
+ throw WRONG_LENGTH;
+
+ if (Codec.codec_context.sample_rate != rate)
+ {
+ dsyslog("dxr3: audiodecoder: sample rate=%d",
+ Codec.codec_context.sample_rate);
+ if (rate != -1) throw UNEXPECTED_PARAMETER_CHANGE;
+ rate = Codec.codec_context.sample_rate;
+ }
+ if (Codec.codec_context.channels != channels + 1)
+ {
+ dsyslog("dxr3: audiodecoder: channels=%d",
+ Codec.codec_context.channels);
+ if (channels != -1)
+ throw UNEXPECTED_PARAMETER_CHANGE;
+ channels = (Codec.codec_context.channels == 2) ? 1 : 0;
+ }
+ if (out_size)
+ {
+ cFixedLengthFrame* pTempFrame = aBuf.Push(pcmbuf,
+ out_size, pts);
+ pTempFrame->SetChannelCount(channels);
+ pTempFrame->SetDataRate(rate);
+ }
+ length -= len;
+ buf += len;
+ }
+ }
+ catch (audioException ex)
+ {
+ switch (ex)
+ {
+ case WRONG_LENGTH:
+ esyslog("dxr3: audiodecoder: wrong length");
+ break;
+
+ case UNEXPECTED_PARAMETER_CHANGE:
+ esyslog("dxr3: audiodecoder: unexpected parameter change");
+ break;
+
+ default:
+ esyslog("dxr3: audiodecoder: unexpected exception");
+ break;
+ }
+ esyslog("dxr3: audiodecoder: skipping %d broken data bytes", length);
+
+ Init();
+ }
+}
+
+// ==================================
+//! decode lpcm
+void cDxr3AudioDecoder::DecodeLpcm(const uint8_t* buf, int length,
+ uint32_t pts, cDxr3SyncBuffer &aBuf)
+{
+ if (length > (LPCM_HEADER_LENGTH + 2))
+ {
+ uint8_t* pFrame = new uint8_t[length - LPCM_HEADER_LENGTH];
+ // only even number of bytes are allowed
+ assert(!((length - LPCM_HEADER_LENGTH) % 2));
+
+ for (int i = LPCM_HEADER_LENGTH; i < length; i += 2)
+ {
+ pFrame[i - LPCM_HEADER_LENGTH] = buf[i + 1];
+ pFrame[i - LPCM_HEADER_LENGTH + 1] = buf[i];
+ }
+
+ int codedSpeed = (buf[5] >> 4) & 0x03;
+ int speed = 0;
+
+ switch (codedSpeed)
+ {
+ case 1:
+ speed = 96000;
+ break;
+
+ case 2:
+ speed = 44100;
+ break;
+
+ case 3:
+ speed = 32000;
+ break;
+
+ default:
+ speed = 48000;
+ break;
+ }
+
+ cFixedLengthFrame* pTempFrame = aBuf.Push(pFrame,
+ length - LPCM_HEADER_LENGTH,
+ pts);
+ pTempFrame->SetChannelCount(1);
+ pTempFrame->SetDataRate(speed);
+
+ delete[] pFrame;
+ }
+}
+
+// ==================================
+//! decode ac3
+void cDxr3AudioDecoder::DecodeAc3Dts(const uint8_t* pPes, const uint8_t* buf,
+ int length, uint32_t pts,
+ cDxr3SyncBuffer &aBuf)
+{
+ int headerLength = (int) (buf - pPes);
+
+ uint8_t* pBuf = (uint8_t*) pPes;
+ ac3dtsDecoder.Check(pBuf + headerLength, length, pBuf);
+ ac3dtsDecoder.Encapsulate(pBuf + headerLength, length);
+
+ cFrame* pFrame = 0;
+ while ((pFrame = rbuf.Get()))
+ {
+ if (pFrame && pFrame->Count())
+ {
+ cDxr3PesFrame tempPes;
+ tempPes.ExtractNextFrame(pFrame->Data(), pFrame->Count());
+ int pesHeaderLength = (int) (tempPes.GetEsStart() - tempPes.GetPesStart());
+ uint8_t* pData = pFrame->Data() + pesHeaderLength + LPCM_HEADER_LENGTH;
+
+ for (int i = 0; i < pFrame->Count() - pesHeaderLength - LPCM_HEADER_LENGTH; i += 2)
+ {
+ std::swap(pData[i], pData[i + 1]);
+ }
+
+ aBuf.Push(pFrame->Data() + pesHeaderLength + LPCM_HEADER_LENGTH, pFrame->Count() - pesHeaderLength - 7, tempPes.GetPts());
+ if (pFrame) rbuf.Drop(pFrame);
+ }
+ }
+}
+
+// ==================================
+//! checking routine
+bool cDxr3AudioDecoder::HeadCheck(unsigned long head)
+{
+ bool retval = false;
+
+ uint8_t* phead = (uint8_t*) (&head);
+ if (phead[0] != 0xFF)
+ {
+ retval = false;
+ }
+ else if (phead[1] != 0xFC && phead[1] != 0xFE)
+ {
+ retval = false;
+ }
+ else if ((phead[2] & 0xF0) == 0xF0)
+ {
+ retval = false;
+ }
+ else if ((phead[2] & 0xC) == 0xC)
+ {
+ retval = false;
+ }
+ else
+ {
+ retval = true;
+ }
+
+ return retval;
+}
+
+// Local variables:
+// mode: c++
+// c-file-style: "stroustrup"
+// c-file-offsets: ((inline-open . 0))
+// indent-tabs-mode: t
+// End:
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