3 * Copyright (c) 2011 Max Horn
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
30 * Demuxer for xWMA, a Microsoft audio container used by XAudio 2.
33 typedef struct XWMAContext {
37 static int xwma_probe(AVProbeData *p)
39 if (!memcmp(p->buf, "RIFF", 4) && !memcmp(p->buf + 8, "XWMA", 4))
40 return AVPROBE_SCORE_MAX;
44 static int xwma_read_header(AVFormatContext *s)
48 uint32_t dpds_table_size = 0;
49 uint32_t *dpds_table = NULL;
51 AVIOContext *pb = s->pb;
53 XWMAContext *xwma = s->priv_data;
56 /* The following code is mostly copied from wav.c, with some
60 /* check RIFF header */
62 if (tag != MKTAG('R', 'I', 'F', 'F'))
64 avio_rl32(pb); /* file size */
66 if (tag != MKTAG('X', 'W', 'M', 'A'))
69 /* parse fmt header */
71 if (tag != MKTAG('f', 'm', 't', ' '))
74 st = avformat_new_stream(s, NULL);
76 return AVERROR(ENOMEM);
78 ret = ff_get_wav_header(s, pb, st->codecpar, size, 0);
81 st->need_parsing = AVSTREAM_PARSE_NONE;
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
88 if (st->codecpar->codec_id != AV_CODEC_ID_WMAV2 &&
89 st->codecpar->codec_id != AV_CODEC_ID_WMAPRO) {
90 avpriv_request_sample(s, "Unexpected codec (tag %s; id %d)",
91 av_fourcc2str(st->codecpar->codec_tag),
92 st->codecpar->codec_id);
94 /* In all xWMA files I have seen, there is no extradata. But the WMA
95 * codecs require extradata, so we provide our own fake extradata.
97 * First, check that there really was no extradata in the header. If
98 * there was, then try to use it, after asking the user to provide a
99 * sample of this unusual file.
101 if (st->codecpar->extradata_size != 0) {
102 /* Surprise, surprise: We *did* get some extradata. No idea
103 * if it will work, but just go on and try it, after asking
104 * the user for a sample.
106 avpriv_request_sample(s, "Unexpected extradata (%d bytes)",
107 st->codecpar->extradata_size);
108 } else if (st->codecpar->codec_id == AV_CODEC_ID_WMAPRO) {
109 if (ff_alloc_extradata(st->codecpar, 18))
110 return AVERROR(ENOMEM);
112 memset(st->codecpar->extradata, 0, st->codecpar->extradata_size);
113 st->codecpar->extradata[ 0] = st->codecpar->bits_per_coded_sample;
114 st->codecpar->extradata[14] = 224;
116 if (ff_alloc_extradata(st->codecpar, 6))
117 return AVERROR(ENOMEM);
119 memset(st->codecpar->extradata, 0, st->codecpar->extradata_size);
120 /* setup extradata with our experimentally obtained value */
121 st->codecpar->extradata[4] = 31;
125 if (!st->codecpar->channels) {
126 av_log(s, AV_LOG_WARNING, "Invalid channel count: %d\n",
127 st->codecpar->channels);
128 return AVERROR_INVALIDDATA;
130 if (!st->codecpar->bits_per_coded_sample) {
131 av_log(s, AV_LOG_WARNING, "Invalid bits_per_coded_sample: %d\n",
132 st->codecpar->bits_per_coded_sample);
133 return AVERROR_INVALIDDATA;
136 /* set the sample rate */
137 avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
139 /* parse the remaining RIFF chunks */
141 if (pb->eof_reached) {
145 /* read next chunk tag */
147 size = avio_rl32(pb);
148 if (tag == MKTAG('d', 'a', 't', 'a')) {
149 /* We assume that the data chunk comes last. */
151 } else if (tag == MKTAG('d','p','d','s')) {
152 /* Quoting the MSDN xWMA docs on the dpds chunk: "Contains the
153 * decoded packet cumulative data size array, each element is the
154 * number of bytes accumulated after the corresponding xWMA packet
155 * is decoded in order."
157 * Each packet has size equal to st->codecpar->block_align, which in
158 * all cases I saw so far was always 2230. Thus, we can use the
159 * dpds data to compute a seeking index.
162 /* Error out if there is more than one dpds chunk. */
164 av_log(s, AV_LOG_ERROR, "two dpds chunks present\n");
165 ret = AVERROR_INVALIDDATA;
169 /* Compute the number of entries in the dpds chunk. */
170 if (size & 3) { /* Size should be divisible by four */
171 av_log(s, AV_LOG_WARNING,
172 "dpds chunk size %"PRId64" not divisible by 4\n", size);
174 dpds_table_size = size / 4;
175 if (dpds_table_size == 0 || dpds_table_size >= INT_MAX / 4) {
176 av_log(s, AV_LOG_ERROR,
177 "dpds chunk size %"PRId64" invalid\n", size);
178 return AVERROR_INVALIDDATA;
181 /* Allocate some temporary storage to keep the dpds data around.
182 * for processing later on.
184 dpds_table = av_malloc_array(dpds_table_size, sizeof(uint32_t));
186 return AVERROR(ENOMEM);
189 for (i = 0; i < dpds_table_size; ++i) {
190 dpds_table[i] = avio_rl32(pb);
197 /* Determine overall data length */
199 ret = AVERROR_INVALIDDATA;
203 xwma->data_end = INT64_MAX;
205 xwma->data_end = avio_tell(pb) + size;
208 if (dpds_table && dpds_table_size) {
210 const uint32_t bytes_per_sample
211 = (st->codecpar->channels * st->codecpar->bits_per_coded_sample) >> 3;
213 /* Estimate the duration from the total number of output bytes. */
214 const uint64_t total_decoded_bytes = dpds_table[dpds_table_size - 1];
216 if (!bytes_per_sample) {
217 av_log(s, AV_LOG_ERROR,
218 "Invalid bits_per_coded_sample %d for %d channels\n",
219 st->codecpar->bits_per_coded_sample, st->codecpar->channels);
220 ret = AVERROR_INVALIDDATA;
224 st->duration = total_decoded_bytes / bytes_per_sample;
226 /* Use the dpds data to build a seek table. We can only do this after
227 * we know the offset to the data chunk, as we need that to determine
228 * the actual offset to each input block.
229 * Note: If we allowed ourselves to assume that the data chunk always
230 * follows immediately after the dpds block, we could of course guess
231 * the data block's start offset already while reading the dpds chunk.
232 * I decided against that, just in case other chunks ever are
235 cur_pos = avio_tell(pb);
236 for (i = 0; i < dpds_table_size; ++i) {
237 /* From the number of output bytes that would accumulate in the
238 * output buffer after decoding the first (i+1) packets, we compute
239 * an offset / timestamp pair.
241 av_add_index_entry(st,
242 cur_pos + (i+1) * st->codecpar->block_align, /* pos */
243 dpds_table[i] / bytes_per_sample, /* timestamp */
244 st->codecpar->block_align, /* size */
248 } else if (st->codecpar->bit_rate) {
249 /* No dpds chunk was present (or only an empty one), so estimate
250 * the total duration using the average bits per sample and the
253 st->duration = (size<<3) * st->codecpar->sample_rate / st->codecpar->bit_rate;
262 static int xwma_read_packet(AVFormatContext *s, AVPacket *pkt)
267 XWMAContext *xwma = s->priv_data;
271 left = xwma->data_end - avio_tell(s->pb);
276 /* read a single block; the default block size is 2230. */
277 size = (st->codecpar->block_align > 1) ? st->codecpar->block_align : 2230;
278 size = FFMIN(size, left);
280 ret = av_get_packet(s->pb, pkt, size);
284 pkt->stream_index = 0;
288 AVInputFormat ff_xwma_demuxer = {
290 .long_name = NULL_IF_CONFIG_SMALL("Microsoft xWMA"),
291 .priv_data_size = sizeof(XWMAContext),
292 .read_probe = xwma_probe,
293 .read_header = xwma_read_header,
294 .read_packet = xwma_read_packet,