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2ba45a60 DM |
1 | /* |
2 | * xWMA demuxer | |
3 | * Copyright (c) 2011 Max Horn | |
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 <inttypes.h> | |
23 | #include <stdint.h> | |
24 | ||
25 | #include "avformat.h" | |
26 | #include "internal.h" | |
27 | #include "riff.h" | |
28 | ||
29 | /* | |
30 | * Demuxer for xWMA, a Microsoft audio container used by XAudio 2. | |
31 | */ | |
32 | ||
33 | typedef struct { | |
34 | int64_t data_end; | |
35 | } XWMAContext; | |
36 | ||
37 | static int xwma_probe(AVProbeData *p) | |
38 | { | |
39 | if (!memcmp(p->buf, "RIFF", 4) && !memcmp(p->buf + 8, "XWMA", 4)) | |
40 | return AVPROBE_SCORE_MAX; | |
41 | return 0; | |
42 | } | |
43 | ||
44 | static int xwma_read_header(AVFormatContext *s) | |
45 | { | |
46 | int64_t size; | |
f6fa7814 | 47 | int ret = 0; |
2ba45a60 DM |
48 | uint32_t dpds_table_size = 0; |
49 | uint32_t *dpds_table = NULL; | |
50 | unsigned int tag; | |
51 | AVIOContext *pb = s->pb; | |
52 | AVStream *st; | |
53 | XWMAContext *xwma = s->priv_data; | |
54 | int i; | |
55 | ||
56 | /* The following code is mostly copied from wav.c, with some | |
57 | * minor alterations. | |
58 | */ | |
59 | ||
60 | /* check RIFF header */ | |
61 | tag = avio_rl32(pb); | |
62 | if (tag != MKTAG('R', 'I', 'F', 'F')) | |
63 | return -1; | |
64 | avio_rl32(pb); /* file size */ | |
65 | tag = avio_rl32(pb); | |
66 | if (tag != MKTAG('X', 'W', 'M', 'A')) | |
67 | return -1; | |
68 | ||
69 | /* parse fmt header */ | |
70 | tag = avio_rl32(pb); | |
71 | if (tag != MKTAG('f', 'm', 't', ' ')) | |
72 | return -1; | |
73 | size = avio_rl32(pb); | |
74 | st = avformat_new_stream(s, NULL); | |
75 | if (!st) | |
76 | return AVERROR(ENOMEM); | |
77 | ||
78 | ret = ff_get_wav_header(pb, st->codec, size); | |
79 | if (ret < 0) | |
80 | return ret; | |
81 | st->need_parsing = AVSTREAM_PARSE_NONE; | |
82 | ||
83 | /* All xWMA files I have seen contained WMAv2 data. If there are files | |
84 | * using WMA Pro or some other codec, then we need to figure out the right | |
85 | * extradata for that. Thus, ask the user for feedback, but try to go on | |
86 | * anyway. | |
87 | */ | |
88 | if (st->codec->codec_id != AV_CODEC_ID_WMAV2) { | |
89 | avpriv_request_sample(s, "Unexpected codec (tag 0x04%x; id %d)", | |
90 | st->codec->codec_tag, st->codec->codec_id); | |
91 | } else { | |
92 | /* In all xWMA files I have seen, there is no extradata. But the WMA | |
93 | * codecs require extradata, so we provide our own fake extradata. | |
94 | * | |
95 | * First, check that there really was no extradata in the header. If | |
96 | * there was, then try to use it, after asking the user to provide a | |
97 | * sample of this unusual file. | |
98 | */ | |
99 | if (st->codec->extradata_size != 0) { | |
100 | /* Surprise, surprise: We *did* get some extradata. No idea | |
101 | * if it will work, but just go on and try it, after asking | |
102 | * the user for a sample. | |
103 | */ | |
104 | avpriv_request_sample(s, "Unexpected extradata (%d bytes)", | |
105 | st->codec->extradata_size); | |
106 | } else { | |
107 | st->codec->extradata_size = 6; | |
108 | st->codec->extradata = av_mallocz(6 + FF_INPUT_BUFFER_PADDING_SIZE); | |
109 | if (!st->codec->extradata) | |
110 | return AVERROR(ENOMEM); | |
111 | ||
112 | /* setup extradata with our experimentally obtained value */ | |
113 | st->codec->extradata[4] = 31; | |
114 | } | |
115 | } | |
116 | ||
117 | if (!st->codec->channels) { | |
118 | av_log(s, AV_LOG_WARNING, "Invalid channel count: %d\n", | |
119 | st->codec->channels); | |
120 | return AVERROR_INVALIDDATA; | |
121 | } | |
122 | if (!st->codec->bits_per_coded_sample) { | |
123 | av_log(s, AV_LOG_WARNING, "Invalid bits_per_coded_sample: %d\n", | |
124 | st->codec->bits_per_coded_sample); | |
125 | return AVERROR_INVALIDDATA; | |
126 | } | |
127 | ||
128 | /* set the sample rate */ | |
129 | avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate); | |
130 | ||
131 | /* parse the remaining RIFF chunks */ | |
132 | for (;;) { | |
133 | if (pb->eof_reached) { | |
134 | ret = AVERROR_EOF; | |
f6fa7814 | 135 | goto fail; |
2ba45a60 DM |
136 | } |
137 | /* read next chunk tag */ | |
138 | tag = avio_rl32(pb); | |
139 | size = avio_rl32(pb); | |
140 | if (tag == MKTAG('d', 'a', 't', 'a')) { | |
141 | /* We assume that the data chunk comes last. */ | |
142 | break; | |
143 | } else if (tag == MKTAG('d','p','d','s')) { | |
144 | /* Quoting the MSDN xWMA docs on the dpds chunk: "Contains the | |
145 | * decoded packet cumulative data size array, each element is the | |
146 | * number of bytes accumulated after the corresponding xWMA packet | |
147 | * is decoded in order." | |
148 | * | |
149 | * Each packet has size equal to st->codec->block_align, which in | |
150 | * all cases I saw so far was always 2230. Thus, we can use the | |
151 | * dpds data to compute a seeking index. | |
152 | */ | |
153 | ||
154 | /* Error out if there is more than one dpds chunk. */ | |
155 | if (dpds_table) { | |
156 | av_log(s, AV_LOG_ERROR, "two dpds chunks present\n"); | |
157 | ret = AVERROR_INVALIDDATA; | |
f6fa7814 | 158 | goto fail; |
2ba45a60 DM |
159 | } |
160 | ||
161 | /* Compute the number of entries in the dpds chunk. */ | |
162 | if (size & 3) { /* Size should be divisible by four */ | |
163 | av_log(s, AV_LOG_WARNING, | |
164 | "dpds chunk size %"PRId64" not divisible by 4\n", size); | |
165 | } | |
166 | dpds_table_size = size / 4; | |
167 | if (dpds_table_size == 0 || dpds_table_size >= INT_MAX / 4) { | |
168 | av_log(s, AV_LOG_ERROR, | |
169 | "dpds chunk size %"PRId64" invalid\n", size); | |
170 | return AVERROR_INVALIDDATA; | |
171 | } | |
172 | ||
173 | /* Allocate some temporary storage to keep the dpds data around. | |
174 | * for processing later on. | |
175 | */ | |
176 | dpds_table = av_malloc(dpds_table_size * sizeof(uint32_t)); | |
177 | if (!dpds_table) { | |
178 | return AVERROR(ENOMEM); | |
179 | } | |
180 | ||
181 | for (i = 0; i < dpds_table_size; ++i) { | |
182 | dpds_table[i] = avio_rl32(pb); | |
183 | size -= 4; | |
184 | } | |
185 | } | |
186 | avio_skip(pb, size); | |
187 | } | |
188 | ||
189 | /* Determine overall data length */ | |
190 | if (size < 0) { | |
191 | ret = AVERROR_INVALIDDATA; | |
f6fa7814 | 192 | goto fail; |
2ba45a60 DM |
193 | } |
194 | if (!size) { | |
195 | xwma->data_end = INT64_MAX; | |
196 | } else | |
197 | xwma->data_end = avio_tell(pb) + size; | |
198 | ||
199 | ||
200 | if (dpds_table && dpds_table_size) { | |
201 | int64_t cur_pos; | |
202 | const uint32_t bytes_per_sample | |
203 | = (st->codec->channels * st->codec->bits_per_coded_sample) >> 3; | |
204 | ||
205 | /* Estimate the duration from the total number of output bytes. */ | |
206 | const uint64_t total_decoded_bytes = dpds_table[dpds_table_size - 1]; | |
207 | ||
208 | if (!bytes_per_sample) { | |
209 | av_log(s, AV_LOG_ERROR, | |
210 | "Invalid bits_per_coded_sample %d for %d channels\n", | |
211 | st->codec->bits_per_coded_sample, st->codec->channels); | |
212 | ret = AVERROR_INVALIDDATA; | |
f6fa7814 | 213 | goto fail; |
2ba45a60 DM |
214 | } |
215 | ||
216 | st->duration = total_decoded_bytes / bytes_per_sample; | |
217 | ||
218 | /* Use the dpds data to build a seek table. We can only do this after | |
219 | * we know the offset to the data chunk, as we need that to determine | |
220 | * the actual offset to each input block. | |
221 | * Note: If we allowed ourselves to assume that the data chunk always | |
222 | * follows immediately after the dpds block, we could of course guess | |
223 | * the data block's start offset already while reading the dpds chunk. | |
224 | * I decided against that, just in case other chunks ever are | |
225 | * discovered. | |
226 | */ | |
227 | cur_pos = avio_tell(pb); | |
228 | for (i = 0; i < dpds_table_size; ++i) { | |
229 | /* From the number of output bytes that would accumulate in the | |
230 | * output buffer after decoding the first (i+1) packets, we compute | |
231 | * an offset / timestamp pair. | |
232 | */ | |
233 | av_add_index_entry(st, | |
234 | cur_pos + (i+1) * st->codec->block_align, /* pos */ | |
235 | dpds_table[i] / bytes_per_sample, /* timestamp */ | |
236 | st->codec->block_align, /* size */ | |
237 | 0, /* duration */ | |
238 | AVINDEX_KEYFRAME); | |
239 | } | |
240 | } else if (st->codec->bit_rate) { | |
241 | /* No dpds chunk was present (or only an empty one), so estimate | |
242 | * the total duration using the average bits per sample and the | |
243 | * total data length. | |
244 | */ | |
245 | st->duration = (size<<3) * st->codec->sample_rate / st->codec->bit_rate; | |
246 | } | |
247 | ||
f6fa7814 | 248 | fail: |
2ba45a60 DM |
249 | av_free(dpds_table); |
250 | ||
251 | return ret; | |
252 | } | |
253 | ||
254 | static int xwma_read_packet(AVFormatContext *s, AVPacket *pkt) | |
255 | { | |
256 | int ret, size; | |
257 | int64_t left; | |
258 | AVStream *st; | |
259 | XWMAContext *xwma = s->priv_data; | |
260 | ||
261 | st = s->streams[0]; | |
262 | ||
263 | left = xwma->data_end - avio_tell(s->pb); | |
264 | if (left <= 0) { | |
265 | return AVERROR_EOF; | |
266 | } | |
267 | ||
268 | /* read a single block; the default block size is 2230. */ | |
269 | size = (st->codec->block_align > 1) ? st->codec->block_align : 2230; | |
270 | size = FFMIN(size, left); | |
271 | ||
272 | ret = av_get_packet(s->pb, pkt, size); | |
273 | if (ret < 0) | |
274 | return ret; | |
275 | ||
276 | pkt->stream_index = 0; | |
277 | return ret; | |
278 | } | |
279 | ||
280 | AVInputFormat ff_xwma_demuxer = { | |
281 | .name = "xwma", | |
282 | .long_name = NULL_IF_CONFIG_SMALL("Microsoft xWMA"), | |
283 | .priv_data_size = sizeof(XWMAContext), | |
284 | .read_probe = xwma_probe, | |
285 | .read_header = xwma_read_header, | |
286 | .read_packet = xwma_read_packet, | |
287 | }; |