[vlc-devel] [PATCH 3/5] demux: mp4: read the 360° yaw/picth/roll with the projection

[Steve Lhomme]

On Thu, Nov 10, 2016 at 3:28 PM, Hugo Beauzée-Luyssen <hugo at beauzee.fr> wrote:
> On 11/10/2016 03:19 PM, Steve Lhomme wrote:
>>
>> ---
>>  modules/demux/mp4/essetup.c |  5 +++++
>>  modules/demux/mp4/libmp4.c  | 30 ++++++++++++++++++++++++++++++
>>  modules/demux/mp4/libmp4.h  |  3 +++
>>  3 files changed, 38 insertions(+)
>>
>> diff --git a/modules/demux/mp4/essetup.c b/modules/demux/mp4/essetup.c
>> index d85bd8b..1aff644 100644
>> --- a/modules/demux/mp4/essetup.c
>> +++ b/modules/demux/mp4/essetup.c
>> @@ -352,7 +352,12 @@ int SetupVideoES( demux_t *p_demux, mp4_track_t
>> *p_track, MP4_Box_t *p_sample )
>>          if( p_uuid->i_type == ATOM_uuid
>>              && !CmpUUID( &p_uuid->i_uuid, &XML360BoxUUID )
>>              && p_uuid->data.p_360 )
>> +        {
>>              p_track->fmt.video.projection_mode =
>> p_uuid->data.p_360->i_projection_mode;
>> +            p_track->fmt.video.f_pose_yaw_degrees =
>> p_uuid->data.p_360->f_heading;
>> +            p_track->fmt.video.f_pose_pitch_degrees =
>> p_uuid->data.p_360->f_pitch;
>> +            p_track->fmt.video.f_pose_roll_degrees =
>> p_uuid->data.p_360->f_roll;
>> +        }
>>      }
>>
>>      /* It's a little ugly but .. there are special cases */
>> diff --git a/modules/demux/mp4/libmp4.c b/modules/demux/mp4/libmp4.c
>> index e121dfe..8cf26ff 100644
>> --- a/modules/demux/mp4/libmp4.c
>> +++ b/modules/demux/mp4/libmp4.c
>> @@ -713,6 +713,26 @@ static int MP4_ReadBox_tfrf(  stream_t *p_stream,
>> MP4_Box_t *p_box )
>>      MP4_READBOX_EXIT( 1 );
>>  }
>>
>> +static bool getRDFFloat(const char *psz_rdf, const char *psz_var, float
>> *out)
>> +{
>> +    size_t varlen = strlen(psz_var);
>
>
> You can compute this after checking if it's worth it I guess

Good point.

>> +    char *p_start = strcasestr( psz_rdf, psz_var );
>> +    if (p_start == NULL)
>> +        return false;
>> +
>> +    char *p_end = strchr( p_start + varlen, '"');
>> +    if (unlikely(p_end == NULL))
>> +        return false;
>> +
>> +    char pose[p_end - p_start + 1];
>> +    memcpy(pose, p_start + varlen, p_end - p_start - varlen);
>> +    pose[p_end - p_start - varlen] = 0;
>> +    if (sscanf(pose, "%f", out) != 1)
>
>
> Couldn't you achieve the same result without memcpy/sscanf by using strtod?

I didn't know about it. I'll have a look.

>
>> +        return false;
>> +
>> +    return true;
>> +}
>> +
>>  static int MP4_ReadBox_XML360( stream_t *p_stream, MP4_Box_t *p_box )
>>  {
>>      MP4_READBOX_ENTER( MP4_Box_data_360_t, NULL );
>> @@ -732,6 +752,16 @@ static int MP4_ReadBox_XML360( stream_t *p_stream,
>> MP4_Box_t *p_box )
>>      if ( strcasestr( psz_rdf, "Gspherical:Spherical" ) )
>>          p_360_data->i_projection_mode = PROJECTION_MODE_EQUIRECTANGULAR;
>>
>> +    float value;
>> +    if (getRDFFloat( psz_rdf, "InitialViewHeadingDegrees=\"", &value ))
>> +        p_360_data->f_heading = value;
>> +
>> +    if (getRDFFloat( psz_rdf, "InitialViewPitchDegrees=\"", &value ))
>> +        p_360_data->f_pitch = value;
>> +
>> +    if (getRDFFloat( psz_rdf, "InitialViewRollDegrees=\"", &value ))
>> +        p_360_data->f_roll = value;
>> +
>>      /* Try to find the stero mode. */
>>      if ( strcasestr( psz_rdf, "left-right" ) )
>>          msg_Dbg( p_stream, "Left-right stereo mode" );
>> diff --git a/modules/demux/mp4/libmp4.h b/modules/demux/mp4/libmp4.h
>> index c72f85a..0209652 100644
>> --- a/modules/demux/mp4/libmp4.h
>> +++ b/modules/demux/mp4/libmp4.h
>> @@ -1541,6 +1541,9 @@ typedef struct
>>  typedef struct
>>  {
>>      uint32_t i_projection_mode;
>> +    float f_heading;
>> +    float f_pitch;
>> +    float f_roll;
>>  } MP4_Box_data_360_t;
>>
>>  /*
>>
>
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