A processing system, comprising: an encoder to encode a real-time transmission of a video presentation; a memory buffer including logically or physically separated first, second and third buffers to copy and store images of the video presentation, wherein the first buffer buffers raw images of the video presentation in an uncoded state; and wherein when an annotation is made on the presentation, a snapshot is taken of a raw image in the first buffer and copied into the second and third buffers which respectively store first and second copies of the snapshot; and a transmitter to transmit a copy of the snapshot to an external annotation device; and a receiver to receive annotation data of an annotation performed on the copy of the snapshot at the external annotation device; wherein the annotation is drawn on the copy of the snapshot stored in the third buffer according to the annotation data in real-time, such that an annotated snapshot is formed in the third buffer and a copy of said annotated snapshot is transmitted to the external annotation device to provide real-time feedback of drawing the annotation on the external annotation device; and wherein the second buffer stores the first copy of the snapshot having no annotation drawn thereon; wherein the encoder encodes the raw images from the first buffer to form the real-time transmission or, when the annotation is being coded into the real-time transmission of the video presentation, the encoder utilizes the annotated snapshot in the third buffer as an annotated raw image to form the real-time transmission; and the processing system includes a clearing annotation feature and the first copy of the snapshot in the second buffer is utilized when the annotation is cleared. an encoder to encode a real-time transmission of a video presentation; a memory buffer including logically or physically separated first, second and third buffers to copy and store images of the video presentation, wherein the first buffer buffers raw images of the video presentation in an uncoded state; and wherein when an annotation is made on the presentation, a snapshot is taken of a raw image in the first buffer and copied into the second and third buffers which respectively store first and second copies of the snapshot; and a transmitter to transmit a copy of the snapshot to an external annotation device; and a receiver to receive annotation data of an annotation performed on the copy of the snapshot at the external annotation device; wherein the annotation is drawn on the copy of the snapshot stored in the third buffer according to the annotation data in real-time, such that an annotated snapshot is formed in the third buffer and a copy of said annotated snapshot is transmitted to the external annotation device to provide real-time feedback of drawing the annotation on the external annotation device; and wherein the second buffer stores the first copy of the snapshot having no annotation drawn thereon; wherein the encoder encodes the raw images from the first buffer to form the real-time transmission or, when the annotation is being coded into the real-time transmission of the video presentation, the encoder utilizes the annotated snapshot in the third buffer as an annotated raw image to form the real-time transmission; and the processing system includes a clearing annotation feature and the first copy of the snapshot in the second buffer is utilized when the annotation is cleared.