[vlc-devel] [PATCH] Added libvlc_video_take_snapshot_addr to libvlc and related functions to libvlccore

[Laurent Aimar]

Hi,

On Mon, Nov 28, 2011 at 08:29:47PM +0100, PaulK wrote:
> Added libvlc_video_take_snapshot_addr to libvlc and related functions to
> libvlccore
> 
> This should fix https://trac.videolan.org/vlc/ticket/2513
> and permits to return a pointer to the (png-encoded) snapshot data
> instead of writing it to a file.

> This should fix https://trac.videolan.org/vlc/ticket/2513
> and permits to return a pointer to the (png-encoded) snapshot data instead of
> writing it to a file.
> ---
>  include/vlc/libvlc_media_player.h |   19 ++++++++
>  lib/libvlc.sym                    |    1 +
>  lib/video.c                       |   40 ++++++++++++++++++
>  src/video_output/vout_intf.c      |   83 +++++++++++++++++++++++++++++++++++++
>  4 files changed, 143 insertions(+), 0 deletions(-)
> 
> diff --git a/include/vlc/libvlc_media_player.h b/include/vlc/libvlc_media_player.h
> index a2b5748..30ed0cd 100644
> --- a/include/vlc/libvlc_media_player.h
> +++ b/include/vlc/libvlc_media_player.h
> @@ -1151,6 +1151,25 @@ int libvlc_video_take_snapshot( libvlc_media_player_t *p_mi, unsigned num,
>                                  unsigned int i_height );
>  
>  /**
> + * Take a snapshot of the current video window and return the snapshot address.
> + *
> + * If i_width AND i_height is 0, original size is used.
> + * If i_width XOR i_height is 0, original aspect-ratio is preserved.
> + *
> + * \param p_mi media player instance
> + * \param num number of video output (typically 0 for the first/only one)
> + * \param psz_addr place to return the snapshot address (you MUST free it after use)
> + * \param i_width the snapshot's width
> + * \param i_height the snapshot's height
> + * \return the snapshot memory area size on success, -1 if there was a problem
> + */
> +LIBVLC_API
> +size_t
> +libvlc_video_take_snapshot_addr( libvlc_media_player_t *p_mi, unsigned num,
> +                                 void **psz_addr, unsigned int i_width, 
> +                                 unsigned int i_height );
> +
> +/**
>   * Enable or disable deinterlace filter
>   *
>   * \param p_mi libvlc media player
> diff --git a/lib/libvlc.sym b/lib/libvlc.sym
> index 6582a96..0a15838 100644
> --- a/lib/libvlc.sym
> +++ b/lib/libvlc.sym
> @@ -216,6 +216,7 @@ libvlc_video_set_subtitle_file
>  libvlc_video_set_teletext
>  libvlc_video_set_track
>  libvlc_video_take_snapshot
> +libvlc_video_take_snapshot_addr
>  libvlc_vlm_add_broadcast
>  libvlc_vlm_add_vod
>  libvlc_vlm_add_input
> diff --git a/lib/video.c b/lib/video.c
> index 6e1ea06..deb45b1 100644
> --- a/lib/video.c
> +++ b/lib/video.c
> @@ -34,6 +34,7 @@
>  #include <vlc/libvlc_media_player.h>
>  
>  #include <vlc_common.h>
> +#include <vlc_block.h>
>  #include <vlc_input.h>
>  #include <vlc_vout.h>
>  
> @@ -158,6 +159,45 @@ libvlc_video_take_snapshot( libvlc_media_player_t *p_mi, unsigned num,
>      return 0;
>  }
>  
> +size_t
> +libvlc_video_take_snapshot_addr( libvlc_media_player_t *p_mi, unsigned num,
> +                                 void **psz_addr, unsigned int i_width, 
> +                                 unsigned int i_height )
> +{
> +    block_t *block_buffer;
> +    size_t buffer_len = 0;
> +    char *buffer = NULL;
> +
> +    vout_thread_t *p_vout = GetVout( p_mi, num );
> +    if (p_vout == NULL)
> +        return -1;
> +
> +    var_SetInteger( p_vout, "snapshot-width", i_width);
> +    var_SetInteger( p_vout, "snapshot-height", i_height );
> +    var_SetString( p_vout, "snapshot-format", "png" );
> +
> +    var_TriggerCallback( p_vout, "video-snapshot-addr" );
> +
> +    block_buffer = (block_t *) var_GetAddress( p_vout, "snapshot-addr" );
> +    if( block_buffer == NULL )
> +        return -1;
> +
> +    buffer_len = block_buffer->i_buffer;
> +    if( buffer_len <= 0 )
> +        return -1;
> +
> +    buffer = malloc( buffer_len );
> +    if( buffer == NULL )
> +        return -1;
> +
> +    psz_addr[0] = buffer;
> +    memcpy( buffer, block_buffer->p_buffer, buffer_len );
> +
> +    var_TriggerCallback( p_vout, "video-snapshot-addr-free" );
> +
> +    return buffer_len;
> +}
I think that you could directly use vout_GetSnapshot() which should
make the code simpler and avoid some race conditions.

Regards,

-- 
fenrir