6 #include "raop_buffer.h"
11 #include "crypto/crypto.h"
12 #include "alac/alac.h"
14 #define RAOP_BUFFER_LENGTH 16
17 /* Packet available */
23 unsigned short seqnum
;
24 unsigned int timestamp
;
27 /* Audio buffer of valid length */
28 int audio_buffer_size
;
31 } raop_buffer_entry_t
;
33 struct raop_buffer_s
{
35 unsigned char aeskey
[RAOP_AESKEY_LEN
];
36 unsigned char aesiv
[RAOP_AESIV_LEN
];
39 ALACSpecificConfig alacConfig
;
42 /* First and last seqnum */
44 unsigned short first_seqnum
;
45 unsigned short last_seqnum
;
47 /* RTP buffer entries */
48 raop_buffer_entry_t entries
[RAOP_BUFFER_LENGTH
];
50 /* Buffer of all audio buffers */
58 get_fmtp_info(ALACSpecificConfig
*config
, const char *fmtp
)
64 /* Parse fmtp string to integers */
65 strptr
= strdup(fmtp
);
66 for (i
=0; i
<12; i
++) {
71 intarr
[i
] = atoi(utils_strsep(&strptr
, " "));
76 /* Fill the config struct */
77 config
->frameLength
= intarr
[1];
78 config
->compatibleVersion
= intarr
[2];
79 config
->bitDepth
= intarr
[3];
80 config
->pb
= intarr
[4];
81 config
->mb
= intarr
[5];
82 config
->kb
= intarr
[6];
83 config
->numChannels
= intarr
[7];
84 config
->maxRun
= intarr
[8];
85 config
->maxFrameBytes
= intarr
[9];
86 config
->avgBitRate
= intarr
[10];
87 config
->sampleRate
= intarr
[11];
89 /* Validate supported audio types */
90 if (config
->bitDepth
!= 16) {
93 if (config
->numChannels
!= 2) {
101 set_decoder_info(alac_file
*alac
, ALACSpecificConfig
*config
)
103 unsigned char decoder_info
[48];
104 memset(decoder_info
, 0, sizeof(decoder_info
));
106 #define SET_UINT16(buf, value)do{\
107 (buf)[0] = (unsigned char)((value) >> 8);\
108 (buf)[1] = (unsigned char)(value);\
111 #define SET_UINT32(buf, value)do{\
112 (buf)[0] = (unsigned char)((value) >> 24);\
113 (buf)[1] = (unsigned char)((value) >> 16);\
114 (buf)[2] = (unsigned char)((value) >> 8);\
115 (buf)[3] = (unsigned char)(value);\
118 /* Construct decoder info buffer */
119 SET_UINT32(&decoder_info
[24], config
->frameLength
);
120 decoder_info
[28] = config
->compatibleVersion
;
121 decoder_info
[29] = config
->bitDepth
;
122 decoder_info
[30] = config
->pb
;
123 decoder_info
[31] = config
->mb
;
124 decoder_info
[32] = config
->kb
;
125 decoder_info
[33] = config
->numChannels
;
126 SET_UINT16(&decoder_info
[34], config
->maxRun
);
127 SET_UINT32(&decoder_info
[36], config
->maxFrameBytes
);
128 SET_UINT32(&decoder_info
[40], config
->avgBitRate
);
129 SET_UINT32(&decoder_info
[44], config
->sampleRate
);
130 alac_set_info(alac
, (char *) decoder_info
);
134 raop_buffer_init(const char *fmtp
,
135 const unsigned char *aeskey
,
136 const unsigned char *aesiv
)
138 raop_buffer_t
*raop_buffer
;
139 int audio_buffer_size
;
140 ALACSpecificConfig
*alacConfig
;
147 raop_buffer
= calloc(1, sizeof(raop_buffer_t
));
152 /* Parse fmtp information */
153 alacConfig
= &raop_buffer
->alacConfig
;
154 if (get_fmtp_info(alacConfig
, fmtp
) < 0) {
159 /* Allocate the output audio buffers */
160 audio_buffer_size
= alacConfig
->frameLength
*
161 alacConfig
->numChannels
*
162 alacConfig
->bitDepth
/8;
163 raop_buffer
->buffer_size
= audio_buffer_size
*
165 raop_buffer
->buffer
= malloc(raop_buffer
->buffer_size
);
166 if (!raop_buffer
->buffer
) {
170 for (i
=0; i
<RAOP_BUFFER_LENGTH
; i
++) {
171 raop_buffer_entry_t
*entry
= &raop_buffer
->entries
[i
];
172 entry
->audio_buffer_size
= audio_buffer_size
;
173 entry
->audio_buffer_len
= 0;
174 entry
->audio_buffer
= raop_buffer
->buffer
+i
*audio_buffer_size
;
177 /* Initialize ALAC decoder */
178 raop_buffer
->alac
= create_alac(alacConfig
->bitDepth
,
179 alacConfig
->numChannels
);
180 if (!raop_buffer
->alac
) {
181 free(raop_buffer
->buffer
);
185 set_decoder_info(raop_buffer
->alac
, alacConfig
);
187 /* Initialize AES keys */
188 memcpy(raop_buffer
->aeskey
, aeskey
, RAOP_AESKEY_LEN
);
189 memcpy(raop_buffer
->aesiv
, aesiv
, RAOP_AESIV_LEN
);
191 /* Mark buffer as empty */
192 raop_buffer
->is_empty
= 1;
197 raop_buffer_destroy(raop_buffer_t
*raop_buffer
)
200 free(raop_buffer
->buffer
);
201 free(raop_buffer
->alac
);
206 const ALACSpecificConfig
*
207 raop_buffer_get_config(raop_buffer_t
*raop_buffer
)
211 return &raop_buffer
->alacConfig
;
215 seqnum_cmp(unsigned short s1
, unsigned short s2
)
221 raop_buffer_queue(raop_buffer_t
*raop_buffer
, unsigned char *data
, unsigned short datalen
, int use_seqnum
)
223 unsigned char packetbuf
[RAOP_PACKET_LEN
];
224 unsigned short seqnum
;
225 raop_buffer_entry_t
*entry
;
232 /* Check packet data length is valid */
233 if (datalen
< 12 || datalen
> RAOP_PACKET_LEN
) {
237 /* Get correct seqnum for the packet */
239 seqnum
= (data
[2] << 8) | data
[3];
241 seqnum
= raop_buffer
->first_seqnum
;
244 /* If this packet is too late, just skip it */
245 if (!raop_buffer
->is_empty
&& seqnum_cmp(seqnum
, raop_buffer
->first_seqnum
) < 0) {
249 /* Check that there is always space in the buffer, otherwise flush */
250 if (seqnum_cmp(seqnum
, raop_buffer
->first_seqnum
+RAOP_BUFFER_LENGTH
) >= 0) {
251 raop_buffer_flush(raop_buffer
, seqnum
);
254 /* Get entry corresponding our seqnum */
255 entry
= &raop_buffer
->entries
[seqnum
% RAOP_BUFFER_LENGTH
];
256 if (entry
->available
&& seqnum_cmp(entry
->seqnum
, seqnum
) == 0) {
257 /* Packet resend, we can safely ignore */
261 /* Update the raop_buffer entry header */
262 entry
->flags
= data
[0];
263 entry
->type
= data
[1];
264 entry
->seqnum
= seqnum
;
265 entry
->timestamp
= (data
[4] << 24) | (data
[5] << 16) |
266 (data
[6] << 8) | data
[7];
267 entry
->ssrc
= (data
[8] << 24) | (data
[9] << 16) |
268 (data
[10] << 8) | data
[11];
269 entry
->available
= 1;
271 /* Decrypt audio data */
272 encryptedlen
= (datalen
-12)/16*16;
273 AES_set_key(&aes_ctx
, raop_buffer
->aeskey
, raop_buffer
->aesiv
, AES_MODE_128
);
274 AES_convert_key(&aes_ctx
);
275 AES_cbc_decrypt(&aes_ctx
, &data
[12], packetbuf
, encryptedlen
);
276 memcpy(packetbuf
+encryptedlen
, &data
[12+encryptedlen
], datalen
-12-encryptedlen
);
278 /* Decode ALAC audio data */
279 outputlen
= entry
->audio_buffer_size
;
280 decode_frame(raop_buffer
->alac
, packetbuf
, entry
->audio_buffer
, &outputlen
);
281 entry
->audio_buffer_len
= outputlen
;
283 /* Update the raop_buffer seqnums */
284 if (raop_buffer
->is_empty
) {
285 raop_buffer
->first_seqnum
= seqnum
;
286 raop_buffer
->last_seqnum
= seqnum
;
287 raop_buffer
->is_empty
= 0;
289 if (seqnum_cmp(seqnum
, raop_buffer
->last_seqnum
) > 0) {
290 raop_buffer
->last_seqnum
= seqnum
;
296 raop_buffer_dequeue(raop_buffer_t
*raop_buffer
, int *length
, int no_resend
)
299 raop_buffer_entry_t
*entry
;
301 /* Calculate number of entries in the current buffer */
302 buflen
= seqnum_cmp(raop_buffer
->last_seqnum
, raop_buffer
->first_seqnum
)+1;
304 /* Cannot dequeue from empty buffer */
305 if (raop_buffer
->is_empty
|| buflen
<= 0) {
309 /* Get the first buffer entry for inspection */
310 entry
= &raop_buffer
->entries
[raop_buffer
->first_seqnum
% RAOP_BUFFER_LENGTH
];
312 /* If we do no resends, always return the first entry */
313 } else if (!entry
->available
) {
314 /* Check how much we have space left in the buffer */
315 if (buflen
< RAOP_BUFFER_LENGTH
) {
316 /* Return nothing and hope resend gets on time */
319 /* Risk of buffer overrun, return empty buffer */
322 /* Update buffer and validate entry */
323 raop_buffer
->first_seqnum
+= 1;
324 if (!entry
->available
) {
325 /* Return an empty audio buffer to skip audio */
326 *length
= entry
->audio_buffer_size
;
327 memset(entry
->audio_buffer
, 0, *length
);
328 return entry
->audio_buffer
;
330 entry
->available
= 0;
332 /* Return entry audio buffer */
333 *length
= entry
->audio_buffer_len
;
334 entry
->audio_buffer_len
= 0;
335 return entry
->audio_buffer
;
339 raop_buffer_handle_resends(raop_buffer_t
*raop_buffer
, raop_resend_cb_t resend_cb
, void *opaque
)
341 raop_buffer_entry_t
*entry
;
346 if (seqnum_cmp(raop_buffer
->first_seqnum
, raop_buffer
->last_seqnum
) < 0) {
349 for (seqnum
=raop_buffer
->first_seqnum
; seqnum_cmp(seqnum
, raop_buffer
->last_seqnum
)<0; seqnum
++) {
350 entry
= &raop_buffer
->entries
[seqnum
% RAOP_BUFFER_LENGTH
];
351 if (entry
->available
) {
355 if (seqnum_cmp(seqnum
, raop_buffer
->first_seqnum
) == 0) {
358 count
= seqnum_cmp(seqnum
, raop_buffer
->first_seqnum
);
359 resend_cb(opaque
, raop_buffer
->first_seqnum
, count
);
364 raop_buffer_flush(raop_buffer_t
*raop_buffer
, int next_seq
)
370 for (i
=0; i
<RAOP_BUFFER_LENGTH
; i
++) {
371 raop_buffer
->entries
[i
].available
= 0;
372 raop_buffer
->entries
[i
].audio_buffer_len
= 0;
374 if (next_seq
< 0 || next_seq
> 0xffff) {
375 raop_buffer
->is_empty
= 1;
377 raop_buffer
->first_seqnum
= next_seq
;
378 raop_buffer
->last_seqnum
= next_seq
-1;