res_format_attr_h264.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2012, Digium, Inc.
 *
 * Joshua Colp <jcolp@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 *
 */
 
/*! \file
 *
 * \brief H.264 Format Attribute Module
 *
 * \author\verbatim Joshua Colp <jcolp@digium.com> \endverbatim
 *
 * This is a format attribute module for the H.264 codec.
 * \ingroup applications
 */
 
/*** MODULEINFO
    <support_level>core</support_level>
 ***/
 
#include "asterisk.h"
 
#include "asterisk/module.h"
#include "asterisk/format.h"
 
/*! \brief Value that indicates an attribute is actually unset */
#define H264_ATTR_KEY_UNSET UINT8_MAX
 
/*! \brief Maximum size for SPS / PPS values in sprop-parameter-sets attribute
 *   if you change this value then you must change H264_MAX_SPS_PPS_SIZE_SCAN_LIMIT
 *   as well. */
#define H264_MAX_SPS_PPS_SIZE 16
/*! \brief This is used when executing sscanf on buffers of H264_MAX_SPS_PPS_SIZE
 *   length. It must ALWAYS be a string literal representation of one less than
 *   H264_MAX_SPS_PPS_SIZE */
#define H264_MAX_SPS_PPS_SIZE_SCAN_LIMIT "15"
 
struct h264_attr {
    unsigned int PROFILE_IDC;
    unsigned int PROFILE_IOP;
    unsigned int LEVEL;
    unsigned int MAX_MBPS;
    unsigned int MAX_FS;
    unsigned int MAX_CPB;
    unsigned int MAX_DPB;
    unsigned int MAX_BR;
    unsigned int MAX_SMBPS;
    unsigned int MAX_FPS;
    unsigned int REDUNDANT_PIC_CAP;
    unsigned int PARAMETER_ADD;
    unsigned int PACKETIZATION_MODE;
    unsigned int SPROP_INTERLEAVING_DEPTH;
    unsigned int SPROP_DEINT_BUF_REQ;
    unsigned int DEINT_BUF_CAP;
    unsigned int SPROP_INIT_BUF_TIME;
    unsigned int SPROP_MAX_DON_DIFF;
    unsigned int MAX_RCMD_NALU_SIZE;
    unsigned int LEVEL_ASYMMETRY_ALLOWED;
    char SPS[H264_MAX_SPS_PPS_SIZE];
    char PPS[H264_MAX_SPS_PPS_SIZE];
};
 
static void h264_destroy(struct ast_format *format)
{
    struct h264_attr *attr = ast_format_get_attribute_data(format);
 
    ast_free(attr);
}
 
static int h264_clone(const struct ast_format *src, struct ast_format *dst)
{
    struct h264_attr *original = ast_format_get_attribute_data(src);
    struct h264_attr *attr = ast_calloc(1, sizeof(*attr));
 
    if (!attr) {
        return -1;
    }
 
    if (original) {
        *attr = *original;
    }
 
    ast_format_set_attribute_data(dst, attr);
 
    return 0;
}
 
static enum ast_format_cmp_res h264_cmp(const struct ast_format *format1, const struct ast_format *format2)
{
    struct h264_attr *attr1 = ast_format_get_attribute_data(format1);
    struct h264_attr *attr2 = ast_format_get_attribute_data(format2);
 
    if (!attr1 || !attr1->PROFILE_IDC || !attr2 || !attr2->PROFILE_IDC ||
        (attr1->PROFILE_IDC == attr2->PROFILE_IDC)) {
        return AST_FORMAT_CMP_EQUAL;
    }
 
    return AST_FORMAT_CMP_NOT_EQUAL;
}
 
#define DETERMINE_JOINT(joint, attr1, attr2, field) (joint->field = (attr1 && attr1->field) ? attr1->field : (attr2 && attr2->field) ? attr2->field : 0)
 
static struct ast_format *h264_getjoint(const struct ast_format *format1, const struct ast_format *format2)
{
    struct ast_format *cloned;
    struct h264_attr *attr, *attr1, *attr2;
 
    cloned = ast_format_clone(format1);
    if (!cloned) {
        return NULL;
    }
    attr = ast_format_get_attribute_data(cloned);
 
    attr1 = ast_format_get_attribute_data(format1);
    attr2 = ast_format_get_attribute_data(format2);
 
    DETERMINE_JOINT(attr, attr1, attr2, PROFILE_IDC);
    DETERMINE_JOINT(attr, attr1, attr2, PROFILE_IOP);
    DETERMINE_JOINT(attr, attr1, attr2, LEVEL);
    DETERMINE_JOINT(attr, attr1, attr2, MAX_MBPS);
    DETERMINE_JOINT(attr, attr1, attr2, MAX_FS);
    DETERMINE_JOINT(attr, attr1, attr2, MAX_CPB);
    DETERMINE_JOINT(attr, attr1, attr2, MAX_DPB);
    DETERMINE_JOINT(attr, attr1, attr2, MAX_BR);
    DETERMINE_JOINT(attr, attr1, attr2, MAX_SMBPS);
    DETERMINE_JOINT(attr, attr1, attr2, MAX_FPS);
    DETERMINE_JOINT(attr, attr1, attr2, REDUNDANT_PIC_CAP);
    DETERMINE_JOINT(attr, attr1, attr2, PARAMETER_ADD);
    DETERMINE_JOINT(attr, attr1, attr2, SPROP_INTERLEAVING_DEPTH);
    DETERMINE_JOINT(attr, attr1, attr2, SPROP_DEINT_BUF_REQ);
    DETERMINE_JOINT(attr, attr1, attr2, DEINT_BUF_CAP);
    DETERMINE_JOINT(attr, attr1, attr2, SPROP_INIT_BUF_TIME);
    DETERMINE_JOINT(attr, attr1, attr2, SPROP_MAX_DON_DIFF);
    DETERMINE_JOINT(attr, attr1, attr2, MAX_RCMD_NALU_SIZE);
    DETERMINE_JOINT(attr, attr1, attr2, LEVEL_ASYMMETRY_ALLOWED);
    DETERMINE_JOINT(attr, attr1, attr2, PACKETIZATION_MODE);
 
    if (attr1 && !ast_strlen_zero(attr1->SPS)) {
        ast_copy_string(attr->SPS, attr1->SPS, sizeof(attr->SPS));
    } else if (attr2 && !ast_strlen_zero(attr2->SPS)) {
        ast_copy_string(attr->SPS, attr2->SPS, sizeof(attr->SPS));
    }
 
    if (attr1 && !ast_strlen_zero(attr1->PPS)) {
        ast_copy_string(attr->PPS, attr1->PPS, sizeof(attr->PPS));
    } else if (attr2 && !ast_strlen_zero(attr2->PPS)) {
        ast_copy_string(attr->PPS, attr2->PPS, sizeof(attr->PPS));
    }
 
    return cloned;
}
 
static struct ast_format *h264_parse_sdp_fmtp(const struct ast_format *format, const char *attributes)
{
    char *attribs = ast_strdupa(attributes), *attrib;
    struct ast_format *cloned;
    struct h264_attr *attr;
 
    cloned = ast_format_clone(format);
    if (!cloned) {
        return NULL;
    }
    attr = ast_format_get_attribute_data(cloned);
 
    attr->REDUNDANT_PIC_CAP = H264_ATTR_KEY_UNSET;
    attr->PARAMETER_ADD = H264_ATTR_KEY_UNSET;
    attr->PACKETIZATION_MODE = H264_ATTR_KEY_UNSET;
    attr->LEVEL_ASYMMETRY_ALLOWED = H264_ATTR_KEY_UNSET;
 
    while ((attrib = strsep(&attribs, ";"))) {
        unsigned int val;
        unsigned long int val2;
 
        attrib = ast_strip(attrib);
 
        if (sscanf(attrib, "profile-level-id=%lx", &val2) == 1) {
            attr->PROFILE_IDC = ((val2 >> 16) & 0xFF);
            attr->PROFILE_IOP = ((val2 >> 8) & 0xFF);
            attr->LEVEL = (val2 & 0xFF);
        } else if (sscanf(attrib, "sprop-parameter-sets=%" H264_MAX_SPS_PPS_SIZE_SCAN_LIMIT "[^','],%" H264_MAX_SPS_PPS_SIZE_SCAN_LIMIT "s", attr->SPS, attr->PPS) == 2) {
            /* XXX sprop-parameter-sets can actually be of unlimited length. This may need to be addressed later. */
        } else if (sscanf(attrib, "max-mbps=%30u", &val) == 1) {
            attr->MAX_MBPS = val;
        } else if (sscanf(attrib, "max-fs=%30u", &val) == 1) {
            attr->MAX_FS = val;
        } else if (sscanf(attrib, "max-cpb=%30u", &val) == 1) {
            attr->MAX_CPB = val;
        } else if (sscanf(attrib, "max-dpb=%30u", &val) == 1) {
            attr->MAX_DPB = val;
        } else if (sscanf(attrib, "max-br=%30u", &val) == 1) {
            attr->MAX_BR = val;
        } else if (sscanf(attrib, "max-smbps=%30u", &val) == 1) {
            attr->MAX_SMBPS = val;
        } else if (sscanf(attrib, "max-fps=%30u", &val) == 1) {
            attr->MAX_FPS = val;
        } else if (sscanf(attrib, "redundant-pic-cap=%30u", &val) == 1) {
            attr->REDUNDANT_PIC_CAP = val;
        } else if (sscanf(attrib, "parameter-add=%30u", &val) == 1) {
            attr->PARAMETER_ADD = val;
        } else if (sscanf(attrib, "packetization-mode=%30u", &val) == 1) {
            attr->PACKETIZATION_MODE = val;
        } else if (sscanf(attrib, "sprop-interleaving-depth=%30u", &val) == 1) {
            attr->SPROP_INTERLEAVING_DEPTH = val;
        } else if (sscanf(attrib, "sprop-deint-buf-req=%30u", &val) == 1) {
            attr->SPROP_DEINT_BUF_REQ = val;
        } else if (sscanf(attrib, "deint-buf-cap=%30u", &val) == 1) {
            attr->DEINT_BUF_CAP = val;
        } else if (sscanf(attrib, "sprop-init-buf-time=%30u", &val) == 1) {
            attr->SPROP_INIT_BUF_TIME = val;
        } else if (sscanf(attrib, "sprop-max-don-diff=%30u", &val) == 1) {
            attr->SPROP_MAX_DON_DIFF = val;
        } else if (sscanf(attrib, "max-rcmd-nalu-size=%30u", &val) == 1) {
            attr->MAX_RCMD_NALU_SIZE = val;
        } else if (sscanf(attrib, "level-asymmetry-allowed=%30u", &val) == 1) {
            attr->LEVEL_ASYMMETRY_ALLOWED = val;
        }
    }
 
    return cloned;
}
 
#define APPEND_IF_NOT_H264_UNSET(field, str, name) do {     \
    if (field != H264_ATTR_KEY_UNSET) { \
        if (added) {    \
            ast_str_append(str, 0, ";");    \
        } else if (0 < ast_str_append(str, 0, "a=fmtp:%u ", payload)) { \
            added = 1;  \
        }   \
        ast_str_append(str, 0, "%s=%u", name, field);   \
    }   \
} while (0)
 
#define APPEND_IF_NONZERO(field, str, name) do {        \
    if (field) {    \
        if (added) {    \
            ast_str_append(str, 0, ";");    \
        } else if (0 < ast_str_append(str, 0, "a=fmtp:%u ", payload)) { \
            added = 1;  \
        }   \
        ast_str_append(str, 0, "%s=%u", name, field);   \
    }   \
} while (0)
 
static void h264_generate_sdp_fmtp(const struct ast_format *format, unsigned int payload, struct ast_str **str)
{
    struct h264_attr *attr = ast_format_get_attribute_data(format);
    int added = 0;
 
    if (!attr) {
        return;
    }
 
    APPEND_IF_NONZERO(attr->MAX_MBPS, str, "max-mbps");
    APPEND_IF_NONZERO(attr->MAX_FS, str, "max-fs");
    APPEND_IF_NONZERO(attr->MAX_CPB, str, "max-cpb");
    APPEND_IF_NONZERO(attr->MAX_DPB, str, "max-dpb");
    APPEND_IF_NONZERO(attr->MAX_BR, str, "max-br");
    APPEND_IF_NONZERO(attr->MAX_SMBPS, str, "max-smbps");
    APPEND_IF_NONZERO(attr->MAX_FPS, str, "max-fps");
    APPEND_IF_NONZERO(attr->SPROP_INTERLEAVING_DEPTH, str, "sprop-interleaving-depth");
    APPEND_IF_NONZERO(attr->SPROP_DEINT_BUF_REQ, str, "sprop-deint-buf-req");
    APPEND_IF_NONZERO(attr->DEINT_BUF_CAP, str, "deint-buf-cap");
    APPEND_IF_NONZERO(attr->SPROP_INIT_BUF_TIME, str, "sprop-init-buf-time");
    APPEND_IF_NONZERO(attr->SPROP_MAX_DON_DIFF, str, "sprop-max-don-diff");
    APPEND_IF_NONZERO(attr->MAX_RCMD_NALU_SIZE, str, "max-rcmd-nalu-size");
 
    APPEND_IF_NOT_H264_UNSET(attr->REDUNDANT_PIC_CAP, str, "redundant-pic-cap");
    APPEND_IF_NOT_H264_UNSET(attr->PARAMETER_ADD, str, "parameter-add");
    APPEND_IF_NOT_H264_UNSET(attr->PACKETIZATION_MODE, str, "packetization-mode");
    APPEND_IF_NOT_H264_UNSET(attr->LEVEL_ASYMMETRY_ALLOWED, str, "level-asymmetry-allowed");
 
    if (attr->PROFILE_IDC && attr->LEVEL) {
        if (added) {
            ast_str_append(str, 0, ";");
        } else if (0 < ast_str_append(str, 0, "a=fmtp:%u ", payload)) {
            added = 1;
        }
        ast_str_append(str, 0, "profile-level-id=%02X%02X%02X", attr->PROFILE_IDC, attr->PROFILE_IOP, attr->LEVEL);
    }
 
    if (!ast_strlen_zero(attr->SPS) && !ast_strlen_zero(attr->PPS)) {
        if (added) {
            ast_str_append(str, 0, ";");
        } else if (0 < ast_str_append(str, 0, "a=fmtp:%u ", payload)) {
            added = 1;
        }
        ast_str_append(str, 0, "sprop-parameter-sets=%s,%s", attr->SPS, attr->PPS);
    }
 
    if (added) {
        ast_str_append(str, 0, "\r\n");
    }
 
    return;
}
 
static struct ast_format_interface h264_interface = {
    .format_destroy = h264_destroy,
    .format_clone = h264_clone,
    .format_cmp = h264_cmp,
    .format_get_joint = h264_getjoint,
    .format_parse_sdp_fmtp = h264_parse_sdp_fmtp,
    .format_generate_sdp_fmtp = h264_generate_sdp_fmtp,
};
 
static int unload_module(void)
{
    return 0;
}
 
static int load_module(void)
{
    if (ast_format_interface_register("h264", &h264_interface)) {
        return AST_MODULE_LOAD_DECLINE;
    }
 
    return AST_MODULE_LOAD_SUCCESS;
}
 
AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_DEFAULT, "H.264 Format Attribute Module",
    .support_level = AST_MODULE_SUPPORT_CORE,
    .load = load_module,
    .unload = unload_module,
);