[vlc-devel] [PATCH 3/8] libvlc: add the API needed to set/get the viewpoint in 360° videos

[Steve Lhomme]

On Thu, Sep 8, 2016 at 5:50 PM, Rémi Denis-Courmont <remi at remlab.net> wrote:
> Le jeudi 8 septembre 2016, 17:35:30 Steve Lhomme a écrit :
>> ---
>>  include/vlc/libvlc_media_player.h | 28 ++++++++++++++++++++++++++++
>>  lib/media_player.c                |  3 +++
>>  lib/video.c                       | 37
>> +++++++++++++++++++++++++++++++++++++ 3 files changed, 68 insertions(+)
>>
>> diff --git a/include/vlc/libvlc_media_player.h
>> b/include/vlc/libvlc_media_player.h index 2718a33..222b25a 100644
>> --- a/include/vlc/libvlc_media_player.h
>> +++ b/include/vlc/libvlc_media_player.h
>> @@ -104,6 +104,16 @@ typedef struct libvlc_audio_output_device_t
>>  } libvlc_audio_output_device_t;
>>
>>  /**
>> + * Viewpoint for video outputs
>> + */
>> +typedef struct libvlc_video_viewpoint_t
>> +{
>> +    float f_yaw;   /**< view point yaw in degrees ]-180;180] */
>> +    float f_pitch; /**< view point pitch in degrees ]-180;180] */
>> +    float f_roll;  /**< view point roll in degrees ]-180;180] */
>> +} libvlc_video_viewpoint_t;
>> +
>> +/**
>>   * Marq options definition
>>   */
>>  typedef enum libvlc_video_marquee_option_t {
>> @@ -1127,6 +1137,24 @@ LIBVLC_API char *libvlc_video_get_aspect_ratio(
>> libvlc_media_player_t *p_mi ); LIBVLC_API void
>> libvlc_video_set_aspect_ratio( libvlc_media_player_t *p_mi, const char
>> *psz_aspect );
>>
>>  /**
>> + * Get current video viewpoint.
>> + *
>> + * \param p_mi the media player
>> + * \return the video viewpoint or NULL if unspecified
>> + * (the result must be released with free() or libvlc_free()).
>> + */
>> +LIBVLC_API libvlc_video_viewpoint_t *libvlc_video_get_viewpoint(
>> libvlc_media_player_t *p_mi ); +
>> +/**
>> + * Set new video viewpoint information.
>> + *
>> + * \param p_mi the media player
>> + * \param psz_aspect new video viewpoint or NULL to reset to default
>> + */
>> +LIBVLC_API void libvlc_video_set_viewpoint( libvlc_media_player_t *p_mi,
>> +                                            const libvlc_video_viewpoint_t
>> *p_viewpoint ); +
>> +/**
>>   * Get current video subtitle.
>>   *
>>   * \param p_mi the media player
>> diff --git a/lib/media_player.c b/lib/media_player.c
>> index 69d3523..197c9be 100644
>> --- a/lib/media_player.c
>> +++ b/lib/media_player.c
>> @@ -640,6 +640,9 @@ libvlc_media_player_new( libvlc_instance_t *instance )
>>      var_Create (mp, "zoom", VLC_VAR_FLOAT | VLC_VAR_DOINHERIT);
>>      var_Create (mp, "aspect-ratio", VLC_VAR_STRING);
>>      var_Create (mp, "crop", VLC_VAR_STRING);
>> +    var_Create (mp, "viewpoint-yaw", VLC_VAR_FLOAT | VLC_VAR_DOINHERIT);
>> +    var_Create (mp, "viewpoint-pitch", VLC_VAR_FLOAT | VLC_VAR_DOINHERIT);
>> +    var_Create (mp, "viewpoint-roll", VLC_VAR_FLOAT | VLC_VAR_DOINHERIT);
>>      var_Create (mp, "deinterlace", VLC_VAR_INTEGER);
>>      var_Create (mp, "deinterlace-mode", VLC_VAR_STRING);
>>
>> diff --git a/lib/video.c b/lib/video.c
>> index b2c9b34..bee4e6d 100644
>> --- a/lib/video.c
>> +++ b/lib/video.c
>> @@ -281,6 +281,43 @@ void libvlc_video_set_aspect_ratio(
>> libvlc_media_player_t *p_mi, free (pp_vouts);
>>  }
>>
>> +libvlc_video_viewpoint_t *libvlc_video_get_viewpoint( libvlc_media_player_t
>> *p_mi )
>> +{
>> +    libvlc_video_viewpoint_t *p_viewpoint =
>> malloc(sizeof(libvlc_video_viewpoint_t));
>> +    if (p_viewpoint == NULL)
>> +        return NULL;
>
> If you want to be able to expand the structure later, this is not enough due
> to libvlc_video_set_viewpoint. And if you don't care, then malloc() seems
> overkill.

I don't understand the issue. You mean expand the structure and remain
libvlc ABI backward compatible ? Is that something we're trying to
achieve ? Also if you expand the structure more memory is allocated
but it's still the same free() that has to be used and should know
about it.

Do you suggest using a get for each of the 3 values ? The viewpoint
will still has to be set with all values at once otherwise you'll end
up with weird transitions between states. And if it's not via a
structure than adding a value will break backward compatibility
anyway.

>> +
>> +    p_viewpoint->f_yaw   = var_GetFloat( p_mi,"viewpoint-yaw" );
>> +    p_viewpoint->f_pitch = var_GetFloat( p_mi,"viewpoint-pitch" );
>> +    p_viewpoint->f_roll  = var_GetFloat( p_mi,"viewpoint-roll" );
>> +    return p_viewpoint;
>> +}
>> +
>> +void libvlc_video_set_viewpoint( libvlc_media_player_t *p_mi,
>> +                                 const libvlc_video_viewpoint_t
>> *p_viewpoint ) +{
>> +    if (p_viewpoint == NULL)
>> +        return;
>> +
>> +    var_SetFloat(p_mi, "viewpoint-yaw", p_viewpoint->f_yaw);
>> +    var_SetFloat(p_mi, "viewpoint-pitch", p_viewpoint->f_pitch);
>> +    var_SetFloat(p_mi, "viewpoint-roll", p_viewpoint->f_roll);
>> +
>> +    char psz_viewpoint[3 * 13];
>> +    sprintf( psz_viewpoint, "%.7f:%.7f:%.7f",
>> +             p_viewpoint->f_yaw, p_viewpoint->f_pitch, p_viewpoint->f_roll
>> ); +    size_t n;
>> +    vout_thread_t **pp_vouts = GetVouts (p_mi, &n);
>> +    for (size_t i = 0; i < n; i++)
>> +    {
>> +        vout_thread_t *p_vout = pp_vouts[i];
>> +
>> +        var_SetString (p_vout, "viewpoint", psz_viewpoint);
>> +        vlc_object_release (p_vout);
>> +    }
>> +    free (pp_vouts);
>> +}
>> +
>>  int libvlc_video_get_spu( libvlc_media_player_t *p_mi )
>>  {
>>      input_thread_t *p_input_thread = libvlc_get_input_thread( p_mi );
>
> --
> Rémi Denis-Courmont
> http://www.remlab.net/
>
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