/*
* QDesign Music 2 (QDM2) payload for RTP
* Copyright (c) 2010 Ronald S. Bultje
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* @brief RTP support for the QDM2 payload (todo: wiki)
* @author Ronald S. Bultje <rbultje@ronald.bitfreak.net>
*/
#include <string.h>
#include "libavutil/avassert.h"
#include "libavutil/intreadwrite.h"
#include "libavcodec/avcodec.h"
#include "internal.h"
#include "rtp.h"
#include "rtpdec.h"
#include "rtpdec_formats.h"
struct PayloadContext {
/** values read from the config header, used as packet headers */
//@{
int block_type; ///< superblock type, value 2 .. 8
int block_size; ///< from extradata, used as pkt length
int subpkts_per_block; ///< max. nr. of subpackets to add per output buffer
//@}
/** Temporary storage for superblock restoring, per packet ID (0x80 total) */
//@{
uint16_t len[0x80]; ///< how much the temporary buffer is filled
uint8_t buf[0x80][0x800]; ///< the temporary storage buffer
unsigned int cache; ///< number of data packets that we have cached right now
unsigned int n_pkts; ///< number of RTP packets received since last packet output / config
uint32_t timestamp; ///< timestamp of next-to-be-returned packet
//@}
};
/**
* Parse configuration (basically the codec-specific extradata) from
* an RTP config subpacket (starts with 0xff).
*
* Layout of the config subpacket (in bytes):
* 1: 0xFF <- config ID
* then an array {
* 1: size <- of the current item
* 1: item type <- 0 .. 4
* size-2: data <- data depends on the item type
* }
*
* Item 0 implies the end of the config subpacket, and has no data.
* Item 1 implies a stream configuration without extradata.
* Item 2 max. nr. of subpackets per superblock
* Item 3 superblock type for the stream
* Item 4 implies a stream configuration with extradata (size >= 0x1c).
*
* @return <0 on error, otherwise the number of bytes parsed from the
* input buffer.
*/
static int qdm2_parse_config(PayloadContext *qdm, AVStream *st,
const uint8_t *buf, const uint8_t *end)
{
const uint8_t *p = buf;
int ret;
while (end - p >= 2) {
unsigned int item_len = p[0], config_item = p[1];
if (item_len < 2 || end - p < item_len || config_item > 4)
return AVERROR_INVALIDDATA;
switch (config_item) {
case 0: /* end of config block */
return p - buf + item_len;
case 1: /* stream without extradata */
/* FIXME: set default qdm->block_size */
break;
case 2: /**< subpackets per block */
if (item_len < 3)
return AVERROR_INVALIDDATA;
qdm->subpkts_per_block = p[2];
break;
case 3: /* superblock type */
if (item_len < 4)
return AVERROR_INVALIDDATA;
qdm->block_type = AV_RB16(p + 2);
break;
case 4: /* stream with extradata */
if (item_len < 30)
return AVERROR_INVALIDDATA;
ret = ff_alloc_extradata(st->codecpar, 26 + item_len);
if (ret < 0) {
return ret;
}
AV_WB32(st->codecpar->extradata, 12);
memcpy(st->codecpar->extradata + 4, "frma", 4);
memcpy(st->codecpar->extradata + 8, "QDM2", 4);
AV_WB32(st->codecpar->extradata + 12, 6 + item_len);
memcpy(st->codecpar->extradata + 16, "QDCA", 4);
memcpy(st->codecpar->extradata + 20, p + 2, item_len - 2);
AV_WB32(st->codecpar->extradata + 18 + item_len, 8);
AV_WB32(st->codecpar->extradata + 22 + item_len, 0);
qdm->block_size = AV_RB32(p + 26);
break;
}
p += item_len;
}
return AVERROR(EAGAIN); /* not enough data */
}
/**
* Parse a single subpacket. We store this subpacket in an intermediate
* buffer (position depends on the ID (byte[0]). When called, at least
* 4 bytes are available for reading (see qdm2_parse_packet()).
*
* Layout of a single subpacket (RTP packets commonly contain multiple
* such subpackets) - length in bytes:
* 1: ordering ID <- 0 .. 0x7F
* 1: subpacket type <- 0 .. 0x7F; value & 0x80 means subpacket length = 2 bytes, else 1 byte
* 1/2: subpacket length <- length of the data following the flags/length fields
* if (subpacket type & 0x7F) == 0x7F
* 1: subpacket type, higher bits
* size: subpacket data
*
* The subpackets come in randomly, and should be encapsulated into 1
* or more superblocks (containing qdm->subpkts_per_block subpackets
* each) per RTP packet, in order of ascending "ordering ID", see
* qdm2_restore_block().
*
* @return <0 on error, otherwise the number of bytes parsed from the
* input buffer.
*/
static int qdm2_parse_subpacket(PayloadContext *qdm, AVStream *st,
const uint8_t *buf, const uint8_t *end)
{
const uint8_t *p = buf;
unsigned int id, len, type, to_copy;
/* parse header so we know the size of the header/data */
id = *p++;
type = *p++;
if (type & 0x80) {
len = AV_RB16(p);
p += 2;
type &= 0x7F;
} else
len = *p++;
if (end - p < len + (type == 0x7F) || id >= 0x80)
return AVERROR_INVALIDDATA;
if (type == 0x7F)
type |= *p++ << 8;
/* copy data into a temporary buffer */
to_copy = FFMIN(len + (p - &buf[1]), 0x800 - qdm->len[id]);
memcpy(&qdm->buf[id][qdm->len[id]], buf + 1, to_copy);
qdm->len[id] += to_copy;
return p + len - buf;
}
/**
* Add a superblock header around a set of subpackets.
*
* @return <0 on error, else 0.
*/
static int qdm2_restore_block(PayloadContext *qdm, AVStream *st, AVPacket *pkt)
{
int to_copy, n, res, include_csum;
uint8_t *p, *csum_pos = NULL;
/* create packet to hold subpkts into a superblock */
av_assert0(qdm->cache > 0);
for (n = 0; n < 0x80; n++)
if (qdm->len[n] > 0)
break;
av_assert0(n < 0x80);
if ((res = av_new_packet(pkt, qdm->block_size)) < 0)
return res;
memset(pkt->data, 0, pkt->size);
pkt->stream_index = st->index;
p = pkt->data;
/* superblock header */
if (qdm->len[n] > 0xff) {
*p++ = qdm->block_type | 0x80;
AV_WB16(p, qdm->len[n]);
p += 2;
} else {
*p++ = qdm->block_type;
*p++ = qdm->len[n];
}
if ((include_csum = (qdm->block_type == 2 || qdm->block_type == 4))) {
csum_pos = p;
p += 2;
}
/* subpacket data */
to_copy = FFMIN(qdm->len[n], pkt->size - (p - pkt->data));
memcpy(p, qdm->buf[n], to_copy);
qdm->len[n] = 0;
/* checksum header */
if (include_csum) {
unsigned int total = 0;
uint8_t *q;
for (q = pkt->data; q < &pkt->data[qdm->block_size]; q++)
total += *q;
AV_WB16(csum_pos, (uint16_t) total);
}
return 0;
}
/** return 0 on packet, no more left, 1 on packet, -1 on partial packet... */
static int qdm2_parse_packet(AVFormatContext *s, PayloadContext *qdm,
AVStream *st, AVPacket *pkt,
uint32_t *timestamp,
const uint8_t *buf, int len, uint16_t seq,
int flags)
{
int res = AVERROR_INVALIDDATA, n;
const uint8_t *end = buf + len, *p = buf;
if (len > 0) {
if (len < 2)
return AVERROR_INVALIDDATA;
/* configuration block */
if (*p == 0xff) {
if (qdm->n_pkts > 0) {
av_log(s, AV_LOG_WARNING,
"Out of sequence config - dropping queue\n");
qdm->n_pkts = 0;
memset(qdm->len, 0, sizeof(qdm->len));
}
if ((res = qdm2_parse_config(qdm, st, ++p, end)) < 0)
return res;
p += res;
/* We set codec_id to AV_CODEC_ID_NONE initially to
* delay decoder initialization since extradata is
* carried within the RTP stream, not SDP. Here,
* by setting codec_id to AV_CODEC_ID_QDM2, we are signalling
* to the decoder that it is OK to initialize. */
st->codecpar->codec_id = AV_CODEC_ID_QDM2;
}
if (st->codecpar->codec_id == AV_CODEC_ID_NONE)
return AVERROR(EAGAIN);
/* subpackets */
while (end - p >= 4) {
if ((res = qdm2_parse_subpacket(qdm, st, p, end)) < 0)
return res;
p += res;
}
qdm->timestamp = *timestamp;
if (++qdm->n_pkts < qdm->subpkts_per_block)
return AVERROR(EAGAIN);
qdm->cache = 0;
for (n = 0; n < 0x80; n++)
if (qdm->len[n] > 0)
qdm->cache++;
}
/* output the subpackets into freshly created superblock structures */
if (!qdm->cache || (res = qdm2_restore_block(qdm, st, pkt)) < 0)
return res;
if (--qdm->cache == 0)
qdm->n_pkts = 0;
*timestamp = qdm->timestamp;
qdm->timestamp = RTP_NOTS_VALUE;
return (qdm->cache > 0) ? 1 : 0;
}
const RTPDynamicProtocolHandler ff_qdm2_dynamic_handler = {
.enc_name = "X-QDM",
.codec_type = AVMEDIA_TYPE_AUDIO,
.codec_id = AV_CODEC_ID_NONE,
.priv_data_size = sizeof(PayloadContext),
.parse_packet = qdm2_parse_packet,
};