/* 
 * Copyright (C) 2011 Teluu Inc. (http://www.teluu.com)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
 */
#ifndef __PJMEDIA_H264_PACKETIZER_H__
#define __PJMEDIA_H264_PACKETIZER_H__

/**
 * @file h264_packetizer.h
 * @brief Packetizes H.264 bitstream into RTP payload and vice versa.
 */

#include <pj/types.h>

PJ_BEGIN_DECL

/**
 * Opaque declaration for H.264 packetizer.
 */
typedef struct pjmedia_h264_packetizer pjmedia_h264_packetizer;


/**
 * Enumeration of H.264 packetization modes.
 */
typedef enum
{
    /**
     * Single NAL unit packetization mode will only generate payloads
     * containing a complete single NAL unit packet. As H.264 NAL unit
     * size can be very large, this mode is usually not applicable for
     * network environments with MTU size limitation.
     */
    PJMEDIA_H264_PACKETIZER_MODE_SINGLE_NAL,
    
    /**
     * Non-interleaved packetization mode will generate payloads with the
     * following possible formats:
     * - single NAL unit packets,
     * - NAL units aggregation STAP-A packets,
     * - fragmented NAL unit FU-A packets.
     */
    PJMEDIA_H264_PACKETIZER_MODE_NON_INTERLEAVED,

    /**
     * Interleaved packetization mode will generate payloads with the
     * following possible formats:
     * - single NAL unit packets,
     * - NAL units aggregation STAP-A & STAP-B packets,
     * - fragmented NAL unit FU-A & FU-B packets.
     * This packetization mode is currently unsupported.
     */
    PJMEDIA_H264_PACKETIZER_MODE_INTERLEAVED,
} pjmedia_h264_packetizer_mode;


/**
 * H.264 packetizer setting.
 */
typedef struct pjmedia_h264_packetizer_cfg
{
    /**
     * Maximum payload length.
     * Default: PJMEDIA_MAX_MTU
     */
    int mtu;

    /**
     * Packetization mode.
     * Default: PJMEDIA_H264_PACKETIZER_MODE_NON_INTERLEAVED
     */
    pjmedia_h264_packetizer_mode mode;

    /**
     * NAL start code size used for unpacketizing.
     * Valid options are 3 (0, 0, 1) or 4 (0, 0, 0, 1).
     * Default: 3 (0, 0, 1)
     */
    unsigned unpack_nal_start;
}
pjmedia_h264_packetizer_cfg;


/**
 * Create H.264 packetizer.
 *
 * @param pool          The memory pool.
 * @param cfg           Packetizer settings, if NULL, default setting
 *                      will be used.
 * @param p_pktz        Pointer to receive the packetizer.
 *
 * @return              PJ_SUCCESS on success.
 */
PJ_DECL(pj_status_t) pjmedia_h264_packetizer_create(
                                    pj_pool_t *pool,
                                    const pjmedia_h264_packetizer_cfg *cfg,
                                    pjmedia_h264_packetizer **p_pktz);


/**
 * Generate an RTP payload from a H.264 picture bitstream. Note that this
 * function will apply in-place processing, so the bitstream may be modified
 * during the packetization.
 *
 * @param pktz          The packetizer.
 * @param bits          The picture bitstream to be packetized.
 * @param bits_len      The length of the bitstream.
 * @param bits_pos      The bitstream offset to be packetized.
 * @param payload       The output payload.
 * @param payload_len   The output payload length.
 *
 * @return              PJ_SUCCESS on success.
 */
PJ_DECL(pj_status_t) pjmedia_h264_packetize(pjmedia_h264_packetizer *pktz,
                                            pj_uint8_t *bits,
                                            pj_size_t bits_len,
                                            unsigned *bits_pos,
                                            const pj_uint8_t **payload,
                                            pj_size_t *payload_len);


/**
 * Append an RTP payload to an H.264 picture bitstream. Note that in case of
 * noticing packet lost, application should keep calling this function with
 * payload pointer set to NULL, as the packetizer need to update its internal
 * state.
 *
 * @param pktz          The packetizer.
 * @param payload       The payload to be unpacketized.
 * @param payload_len   The payload length.
 * @param bits          The bitstream buffer.
 * @param bits_len      The bitstream buffer size.
 * @param bits_pos      The bitstream offset to put the unpacketized payload
 *                      in the bitstream, upon return, this will be updated
 *                      to the latest offset as a result of the unpacketized
 *                      payload.
 *
 * @return              PJ_SUCCESS on success.
 */
PJ_DECL(pj_status_t) pjmedia_h264_unpacketize(pjmedia_h264_packetizer *pktz,
                                              const pj_uint8_t *payload,
                                              pj_size_t   payload_len,
                                              pj_uint8_t *bits,
                                              pj_size_t   bits_len,
                                              unsigned   *bits_pos);


PJ_END_DECL

#endif  /* __PJMEDIA_H264_PACKETIZER_H__ */