1 /*

     2 * Copyright (c) 2010 Ixonos Plc.

     3 * All rights reserved.

     4 * This component and the accompanying materials are made available

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

     6 * which accompanies this distribution, and is available

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

     8 *

     9 * Initial Contributors:

    10 * Nokia Corporation - Initial contribution

    11 *

    12 * Contributors:

    13 * Ixonos Plc

    14 *

    15 * Description:  

    16 * Input stream type determination.

    17 *

    18 */

    19 

    20 

    21 

    22 

    23 /*

    24  * Includes

    25  */

    26 

    27 #include "h263dConfig.h"

    28 

    29 #include "debug.h"

    30 #include "sync.h"

    31 #include "vde.h"

    32 #include "vdemain.h" 

    33 #include "mpegcons.h"

    34 

    35 #include "core.h"

    36 

    37 

    38 /*

    39  * Functions visible outside this module

    40  */

    41 

    42 /*

    43  * vdeDetermineStreamType

    44  *

    45  * Parameters:

    46  *    hInstance                  instance data

    47  *

    48  * Function:

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

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

    51  *   used for the configuration of the decoder. 

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

    53  *   decoding function to set initial parameters.

    54  *

    55  * Returns:

    56  *    VDE_OK                     if the stream type could be detected and 

    57  *                               it is supported

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

    59  *                               the configuration is not supported

    60  *    VDE_ERROR                  if unrecoverable bitbuffer error occered

    61  *

    62  */

    63 int vdeDetermineStreamType(vdeHInstance_t hInstance, CMPEG4Transcoder *hTranscoder)

    64 {

    65    vdeInstance_t *vdeinstance = (vdeInstance_t *) hInstance;

    66    bibBuffer_t *inBuffer = vdeinstance->inBuffer;

    67 

    68    int numBitsGot,

    69       bitErrorIndication = 0;

    70    int16 error = 0;

    71    u_int32 bits;

    72 

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

    74    if (error)

    75       return VDE_ERROR;

    76 

    77    /* If PSC */

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

    79       vdeinstance->fMPEG4 = 0;

    80    } 

    81 

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

    83    else if ((bits == MP4_VOS_START_CODE) || 

    84             (bits == MP4_VO_START_CODE) ||

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

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

    87 

    88       vdeinstance->fMPEG4 = 1;

    89 

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

    91          return VDE_ERROR;

    92 

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

    94       if (error)

    95          return VDE_ERROR;

    96 

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

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

    99       if ( bits == 32 ) {

   100          vdeinstance->fMPEG4 = 0;

   101       }

   102 

   103    }

   104 

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

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

   107    else {

   108       vdeinstance->fMPEG4 = 0;

   109    }

   110 

   111    return VDE_OK;

   112 }

   113 

   114 // End of File