/*

* Copyright (c) 2010 Ixonos Plc.

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - Initial contribution

*

* Contributors:

* Ixonos Plc

*

* Description:  

* Input stream type determination.

*

*/

/*

 * Includes

 */

#include "h263dConfig.h"

#include "debug.h"

#include "sync.h"

#include "vde.h"

#include "vdemain.h" 

#include "mpegcons.h"

#include "core.h"

/*

 * Functions visible outside this module

 */

/*

 * vdeDetermineStreamType

 *

 * Parameters:

 *    hInstance                  instance data

 *

 * Function:

 *   This function detects the stream type, looking at the start code

 *   (h.263 vs. MPEG-4) and sets the flag "fMPEG4" which is

 *   used for the configuration of the decoder. 

 *   In case of an MPEG-4 stream calls the Video Object Header and the VOL Header

 *   decoding function to set initial parameters.

 *

 * Returns:

 *    VDE_OK                     if the stream type could be detected and 

 *                               it is supported

 *    VDE_ERROR_HALTED           if the stream type couldn't be detected or

 *                               the configuration is not supported

 *    VDE_ERROR                  if unrecoverable bitbuffer error occered

 *

 */

int vdeDetermineStreamType(vdeHInstance_t hInstance, CMPEG4Transcoder *hTranscoder)

{

   vdeInstance_t *vdeinstance = (vdeInstance_t *) hInstance;

   bibBuffer_t *inBuffer = vdeinstance->inBuffer;

   int numBitsGot,

      bitErrorIndication = 0;

   int16 error = 0;

   u_int32 bits;

   bits = bibShowBits(32, inBuffer, &numBitsGot, &bitErrorIndication, &error);

   if (error)

      return VDE_ERROR;

   /* If PSC */

   if ((bits >> 10) == 32) {

      vdeinstance->fMPEG4 = 0;

   } 

   /* Else check for Visual Sequence, Visual Object or Video Object start code */

   else if ((bits == MP4_VOS_START_CODE) || 

            (bits == MP4_VO_START_CODE) ||

            ((bits >> MP4_VID_ID_CODE_LENGTH) == MP4_VID_START_CODE) ||

            ((bits >> MP4_VOL_ID_CODE_LENGTH) == MP4_VOL_START_CODE)) {

      vdeinstance->fMPEG4 = 1;

      if (vdcDecodeMPEGVolHeader(vdeinstance->vdcHInstance, inBuffer, hTranscoder) != 0)

         return VDE_ERROR;

      bits = bibShowBits(22, inBuffer, &numBitsGot, &bitErrorIndication, &error);

      if (error)

         return VDE_ERROR;

      /* Check if H.263 PSC follows the VOL header, in which case this is 

         MPEG-4 with short header and is decoded as H.263 */

      if ( bits == 32 ) {

         vdeinstance->fMPEG4 = 0;

      }

   }

   /* Else no H.263 and no MPEG-4 start code detected -> let's try H.263,

      since MPEG-4 cannot anyway be decoded without starting header */

   else {

      vdeinstance->fMPEG4 = 0;

   }

   return VDE_OK;

}

// End of File