2 * QDesign Music 2 (QDM2) payload for RTP
3 * Copyright (c) 2010 Ronald S. Bultje
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 * @brief RTP support for the QDM2 payload (todo: wiki)
25 * @author Ronald S. Bultje <rbultje@ronald.bitfreak.net>
29 #include "libavutil/avassert.h"
30 #include "libavutil/intreadwrite.h"
31 #include "libavcodec/avcodec.h"
35 #include "rtpdec_formats.h"
37 struct PayloadContext
{
38 /** values read from the config header, used as packet headers */
40 int block_type
; ///< superblock type, value 2 .. 8
41 int block_size
; ///< from extradata, used as pkt length
42 int subpkts_per_block
; ///< max. nr. of subpackets to add per output buffer
45 /** Temporary storage for superblock restoring, per packet ID (0x80 total) */
47 uint16_t len
[0x80]; ///< how much the temporary buffer is filled
48 uint8_t buf
[0x80][0x800]; ///< the temporary storage buffer
50 unsigned int cache
; ///< number of data packets that we have cached right now
51 unsigned int n_pkts
; ///< number of RTP packets received since last packet output / config
52 uint32_t timestamp
; ///< timestamp of next-to-be-returned packet
57 * Parse configuration (basically the codec-specific extradata) from
58 * an RTP config subpacket (starts with 0xff).
60 * Layout of the config subpacket (in bytes):
61 * 1: 0xFF <- config ID
63 * 1: size <- of the current item
64 * 1: item type <- 0 .. 4
65 * size-2: data <- data depends on the item type
68 * Item 0 implies the end of the config subpacket, and has no data.
69 * Item 1 implies a stream configuration without extradata.
70 * Item 2 max. nr. of subpackets per superblock
71 * Item 3 superblock type for the stream
72 * Item 4 implies a stream configuration with extradata (size >= 0x1c).
74 * @return <0 on error, otherwise the number of bytes parsed from the
77 static int qdm2_parse_config(PayloadContext
*qdm
, AVStream
*st
,
78 const uint8_t *buf
, const uint8_t *end
)
80 const uint8_t *p
= buf
;
82 while (end
- p
>= 2) {
83 unsigned int item_len
= p
[0], config_item
= p
[1];
85 if (item_len
< 2 || end
- p
< item_len
|| config_item
> 4)
86 return AVERROR_INVALIDDATA
;
88 switch (config_item
) {
89 case 0: /* end of config block */
90 return p
- buf
+ item_len
;
91 case 1: /* stream without extradata */
92 /* FIXME: set default qdm->block_size */
94 case 2: /**< subpackets per block */
96 return AVERROR_INVALIDDATA
;
97 qdm
->subpkts_per_block
= p
[2];
99 case 3: /* superblock type */
101 return AVERROR_INVALIDDATA
;
102 qdm
->block_type
= AV_RB16(p
+ 2);
104 case 4: /* stream with extradata */
106 return AVERROR_INVALIDDATA
;
107 av_freep(&st
->codec
->extradata
);
108 if (ff_alloc_extradata(st
->codec
, 26 + item_len
)) {
109 return AVERROR(ENOMEM
);
111 AV_WB32(st
->codec
->extradata
, 12);
112 memcpy(st
->codec
->extradata
+ 4, "frma", 4);
113 memcpy(st
->codec
->extradata
+ 8, "QDM2", 4);
114 AV_WB32(st
->codec
->extradata
+ 12, 6 + item_len
);
115 memcpy(st
->codec
->extradata
+ 16, "QDCA", 4);
116 memcpy(st
->codec
->extradata
+ 20, p
+ 2, item_len
- 2);
117 AV_WB32(st
->codec
->extradata
+ 18 + item_len
, 8);
118 AV_WB32(st
->codec
->extradata
+ 22 + item_len
, 0);
120 qdm
->block_size
= AV_RB32(p
+ 26);
127 return AVERROR(EAGAIN
); /* not enough data */
131 * Parse a single subpacket. We store this subpacket in an intermediate
132 * buffer (position depends on the ID (byte[0]). When called, at least
133 * 4 bytes are available for reading (see qdm2_parse_packet()).
135 * Layout of a single subpacket (RTP packets commonly contain multiple
136 * such subpackets) - length in bytes:
137 * 1: ordering ID <- 0 .. 0x7F
138 * 1: subpacket type <- 0 .. 0x7F; value & 0x80 means subpacket length = 2 bytes, else 1 byte
139 * 1/2: subpacket length <- length of the data following the flags/length fields
140 * if (subpacket type & 0x7F) == 0x7F
141 * 1: subpacket type, higher bits
142 * size: subpacket data
144 * The subpackets come in randomly, and should be encapsulated into 1
145 * or more superblocks (containing qdm->subpkts_per_block subpackets
146 * each) per RTP packet, in order of ascending "ordering ID", see
147 * qdm2_restore_block().
149 * @return <0 on error, otherwise the number of bytes parsed from the
152 static int qdm2_parse_subpacket(PayloadContext
*qdm
, AVStream
*st
,
153 const uint8_t *buf
, const uint8_t *end
)
155 const uint8_t *p
= buf
;
156 unsigned int id
, len
, type
, to_copy
;
158 /* parse header so we know the size of the header/data */
168 if (end
- p
< len
+ (type
== 0x7F) || id
>= 0x80)
169 return AVERROR_INVALIDDATA
;
173 /* copy data into a temporary buffer */
174 to_copy
= FFMIN(len
+ (p
- &buf
[1]), 0x800 - qdm
->len
[id
]);
175 memcpy(&qdm
->buf
[id
][qdm
->len
[id
]], buf
+ 1, to_copy
);
176 qdm
->len
[id
] += to_copy
;
178 return p
+ len
- buf
;
182 * Add a superblock header around a set of subpackets.
184 * @return <0 on error, else 0.
186 static int qdm2_restore_block(PayloadContext
*qdm
, AVStream
*st
, AVPacket
*pkt
)
188 int to_copy
, n
, res
, include_csum
;
189 uint8_t *p
, *csum_pos
= NULL
;
191 /* create packet to hold subpkts into a superblock */
192 assert(qdm
->cache
> 0);
193 for (n
= 0; n
< 0x80; n
++)
196 av_assert0(n
< 0x80);
198 if ((res
= av_new_packet(pkt
, qdm
->block_size
)) < 0)
200 memset(pkt
->data
, 0, pkt
->size
);
201 pkt
->stream_index
= st
->index
;
204 /* superblock header */
205 if (qdm
->len
[n
] > 0xff) {
206 *p
++ = qdm
->block_type
| 0x80;
207 AV_WB16(p
, qdm
->len
[n
]);
210 *p
++ = qdm
->block_type
;
213 if ((include_csum
= (qdm
->block_type
== 2 || qdm
->block_type
== 4))) {
219 to_copy
= FFMIN(qdm
->len
[n
], pkt
->size
- (p
- pkt
->data
));
220 memcpy(p
, qdm
->buf
[n
], to_copy
);
223 /* checksum header */
225 unsigned int total
= 0;
228 for (q
= pkt
->data
; q
< &pkt
->data
[qdm
->block_size
]; q
++)
230 AV_WB16(csum_pos
, (uint16_t) total
);
236 /** return 0 on packet, no more left, 1 on packet, -1 on partial packet... */
237 static int qdm2_parse_packet(AVFormatContext
*s
, PayloadContext
*qdm
,
238 AVStream
*st
, AVPacket
*pkt
,
240 const uint8_t *buf
, int len
, uint16_t seq
,
243 int res
= AVERROR_INVALIDDATA
, n
;
244 const uint8_t *end
= buf
+ len
, *p
= buf
;
248 return AVERROR_INVALIDDATA
;
250 /* configuration block */
252 if (qdm
->n_pkts
> 0) {
253 av_log(s
, AV_LOG_WARNING
,
254 "Out of sequence config - dropping queue\n");
256 memset(qdm
->len
, 0, sizeof(qdm
->len
));
259 if ((res
= qdm2_parse_config(qdm
, st
, ++p
, end
)) < 0)
263 /* We set codec_id to AV_CODEC_ID_NONE initially to
264 * delay decoder initialization since extradata is
265 * carried within the RTP stream, not SDP. Here,
266 * by setting codec_id to AV_CODEC_ID_QDM2, we are signalling
267 * to the decoder that it is OK to initialize. */
268 st
->codec
->codec_id
= AV_CODEC_ID_QDM2
;
270 if (st
->codec
->codec_id
== AV_CODEC_ID_NONE
)
271 return AVERROR(EAGAIN
);
274 while (end
- p
>= 4) {
275 if ((res
= qdm2_parse_subpacket(qdm
, st
, p
, end
)) < 0)
280 qdm
->timestamp
= *timestamp
;
281 if (++qdm
->n_pkts
< qdm
->subpkts_per_block
)
282 return AVERROR(EAGAIN
);
284 for (n
= 0; n
< 0x80; n
++)
289 /* output the subpackets into freshly created superblock structures */
290 if (!qdm
->cache
|| (res
= qdm2_restore_block(qdm
, st
, pkt
)) < 0)
292 if (--qdm
->cache
== 0)
295 *timestamp
= qdm
->timestamp
;
296 qdm
->timestamp
= RTP_NOTS_VALUE
;
298 return (qdm
->cache
> 0) ? 1 : 0;
301 static PayloadContext
*qdm2_extradata_new(void)
303 return av_mallocz(sizeof(PayloadContext
));
306 static void qdm2_extradata_free(PayloadContext
*qdm
)
311 RTPDynamicProtocolHandler ff_qdm2_dynamic_handler
= {
313 .codec_type
= AVMEDIA_TYPE_AUDIO
,
314 .codec_id
= AV_CODEC_ID_NONE
,
315 .alloc
= qdm2_extradata_new
,
316 .free
= qdm2_extradata_free
,
317 .parse_packet
= qdm2_parse_packet
,