FFmpeg: libavformat/rtpdec_qcelp.c Source File

FFmpeg
rtpdec_qcelp.c
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1 /*
2  * RTP Depacketization of QCELP/PureVoice, RFC 2658
3  * Copyright (c) 2010 Martin Storsjo
4  *
5  * This file is part of FFmpeg.
6  *
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.
11  *
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.
16  *
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
20  */
21 
22 #include "rtpdec_formats.h"
23 
24  static const uint8_t frame_sizes[] = {
25  1, 4, 8, 17, 35
26 };
27 
28  typedef struct {
29   int pos;
30   int size;
31  /* The largest frame is 35 bytes, only 10 frames are allowed per
32  * packet, and we return the first one immediately, so allocate
33  * space for 9 frames */
34   uint8_t data[35*9];
35 } InterleavePacket;
36 
37 struct PayloadContext {
38   int interleave_size;
39   int interleave_index;
40   InterleavePacket group[6];
41   int group_finished;
42 
43  /* The maximum packet size, 10 frames of 35 bytes each, and one
44  * packet header byte. */
45   uint8_t next_data[1 + 35*10];
46   int next_size;
47   uint32_t next_timestamp;
48 };
49 
50  static PayloadContext *qcelp_new_context(void)
51 {
52  return av_mallocz(sizeof(PayloadContext));
53 }
54 
55  static void qcelp_free_context(PayloadContext *data)
56 {
57  av_free(data);
58 }
59 
60 static int return_stored_frame(AVFormatContext *ctx, PayloadContext *data,
61  AVStream *st, AVPacket *pkt, uint32_t *timestamp,
62  const uint8_t *buf, int len);
63 
64  static int store_packet(AVFormatContext *ctx, PayloadContext *data,
65  AVStream *st, AVPacket *pkt, uint32_t *timestamp,
66  const uint8_t *buf, int len)
67 {
68  int interleave_size, interleave_index;
69  int frame_size, ret;
70  InterleavePacket* ip;
71 
72  if (len < 2)
73  return AVERROR_INVALIDDATA;
74 
75  interleave_size = buf[0] >> 3 & 7;
76  interleave_index = buf[0] & 7;
77 
78  if (interleave_size > 5) {
79  av_log(ctx, AV_LOG_ERROR, "Invalid interleave size %d\n",
80  interleave_size);
81  return AVERROR_INVALIDDATA;
82  }
83  if (interleave_index > interleave_size) {
84  av_log(ctx, AV_LOG_ERROR, "Invalid interleave index %d/%d\n",
85  interleave_index, interleave_size);
86  return AVERROR_INVALIDDATA;
87  }
88  if (interleave_size != data->interleave_size) {
89  int i;
90  /* First packet, or changed interleave size */
91  data->interleave_size = interleave_size;
92  data->interleave_index = 0;
93  for (i = 0; i < 6; i++)
94  data->group[i].size = 0;
95  }
96 
97  if (interleave_index < data->interleave_index) {
98  /* Wrapped around - missed the last packet of the previous group. */
99  if (data->group_finished) {
100  /* No more data in the packets in this interleaving group, just
101  * start processing the next one */
102  data->interleave_index = 0;
103  } else {
104  /* Stash away the current packet, emit everything we have of the
105  * previous group. */
106  for (; data->interleave_index <= interleave_size;
107  data->interleave_index++)
108  data->group[data->interleave_index].size = 0;
109 
110  if (len > sizeof(data->next_data))
111  return AVERROR_INVALIDDATA;
112  memcpy(data->next_data, buf, len);
113  data->next_size = len;
114  data->next_timestamp = *timestamp;
115  *timestamp = RTP_NOTS_VALUE;
116 
117  data->interleave_index = 0;
118  return return_stored_frame(ctx, data, st, pkt, timestamp, buf, len);
119  }
120  }
121  if (interleave_index > data->interleave_index) {
122  /* We missed a packet */
123  for (; data->interleave_index < interleave_index;
124  data->interleave_index++)
125  data->group[data->interleave_index].size = 0;
126  }
127  data->interleave_index = interleave_index;
128 
129  if (buf[1] >= FF_ARRAY_ELEMS(frame_sizes))
130  return AVERROR_INVALIDDATA;
131  frame_size = frame_sizes[buf[1]];
132  if (1 + frame_size > len)
133  return AVERROR_INVALIDDATA;
134 
135  if (len - 1 - frame_size > sizeof(data->group[0].data))
136  return AVERROR_INVALIDDATA;
137 
138  if ((ret = av_new_packet(pkt, frame_size)) < 0)
139  return ret;
140  memcpy(pkt->data, &buf[1], frame_size);
141  pkt->stream_index = st->index;
142 
143  ip = &data->group[data->interleave_index];
144  ip->size = len - 1 - frame_size;
145  ip->pos = 0;
146  memcpy(ip->data, &buf[1 + frame_size], ip->size);
147  /* Each packet must contain the same number of frames according to the
148  * RFC. If there's no data left in this packet, there shouldn't be any
149  * in any of the other frames in the interleaving group either. */
150  data->group_finished = ip->size == 0;
151 
152  if (interleave_index == interleave_size) {
153  data->interleave_index = 0;
154  return !data->group_finished;
155  } else {
156  data->interleave_index++;
157  return 0;
158  }
159 }
160 
161  static int return_stored_frame(AVFormatContext *ctx, PayloadContext *data,
162  AVStream *st, AVPacket *pkt, uint32_t *timestamp,
163  const uint8_t *buf, int len)
164 {
165  InterleavePacket* ip = &data->group[data->interleave_index];
166  int frame_size, ret;
167 
168  if (data->group_finished && data->interleave_index == 0) {
169  *timestamp = data->next_timestamp;
170  ret = store_packet(ctx, data, st, pkt, timestamp, data->next_data,
171  data->next_size);
172  data->next_size = 0;
173  return ret;
174  }
175 
176  if (ip->size == 0) {
177  /* No stored data for this interleave block, output an empty packet */
178  if ((ret = av_new_packet(pkt, 1)) < 0)
179  return ret;
180  pkt->data[0] = 0; // Blank - could also be 14, Erasure
181  } else {
182  if (ip->pos >= ip->size)
183  return AVERROR_INVALIDDATA;
184  if (ip->data[ip->pos] >= FF_ARRAY_ELEMS(frame_sizes))
185  return AVERROR_INVALIDDATA;
186  frame_size = frame_sizes[ip->data[ip->pos]];
187  if (ip->pos + frame_size > ip->size)
188  return AVERROR_INVALIDDATA;
189 
190  if ((ret = av_new_packet(pkt, frame_size)) < 0)
191  return ret;
192  memcpy(pkt->data, &ip->data[ip->pos], frame_size);
193 
194  ip->pos += frame_size;
195  data->group_finished = ip->pos >= ip->size;
196  }
197  pkt->stream_index = st->index;
198 
199  if (data->interleave_index == data->interleave_size) {
200  data->interleave_index = 0;
201  if (!data->group_finished)
202  return 1;
203  else
204  return data->next_size > 0;
205  } else {
206  data->interleave_index++;
207  return 1;
208  }
209 }
210 
211  static int qcelp_parse_packet(AVFormatContext *ctx, PayloadContext *data,
212  AVStream *st, AVPacket *pkt, uint32_t *timestamp,
213  const uint8_t *buf, int len, uint16_t seq,
214  int flags)
215 {
216  if (buf)
217  return store_packet(ctx, data, st, pkt, timestamp, buf, len);
218  else
219  return return_stored_frame(ctx, data, st, pkt, timestamp, buf, len);
220 }
221 
222  RTPDynamicProtocolHandler ff_qcelp_dynamic_handler = {
223  .enc_name = "x-Purevoice",
224  .codec_type = AVMEDIA_TYPE_AUDIO,
225  .codec_id = AV_CODEC_ID_QCELP,
226  .static_payload_id = 12,
227  .alloc = qcelp_new_context,
228  .free = qcelp_free_context,
229  .parse_packet = qcelp_parse_packet
230 };
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