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(const 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'))
63 return AVERROR_INVALIDDATA;
64 avio_rl32(pb); /* file size */
66 if (tag != MKTAG('X', 'W', 'M', 'A'))
67 return AVERROR_INVALIDDATA;
69 /* parse fmt header */
71 if (tag != MKTAG('f', 'm', 't', ' '))
72 return AVERROR_INVALIDDATA;
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 /* XWMA encoder only allows a few channel/sample rate/bitrate combinations,
84 * but some create identical files with fake bitrate (1ch 22050hz at
85 * 20/48/192kbps are all 20kbps, with the exact same codec data).
86 * Decoder needs correct bitrate to work, so it's normalized here. */
87 if (st->codecpar->codec_id == AV_CODEC_ID_WMAV2) {
88 int ch = st->codecpar->channels;
89 int sr = st->codecpar->sample_rate;
90 int br = st->codecpar->bit_rate;
93 if (sr == 22050 && (br==48000 || br==192000))
95 else if (sr == 32000 && (br==48000 || br==192000))
97 else if (sr == 44100 && (br==96000 || br==192000))
101 if (sr == 22050 && (br==48000 || br==192000))
103 else if (sr == 32000 && (br==192000))
107 st->codecpar->bit_rate = br;
110 /* Normally xWMA can only contain WMAv2 with 1/2 channels,
111 * and WMAPRO with 6 channels. */
112 if (st->codecpar->codec_id != AV_CODEC_ID_WMAV2 &&
113 st->codecpar->codec_id != AV_CODEC_ID_WMAPRO) {
114 avpriv_request_sample(s, "Unexpected codec (tag %s; id %d)",
115 av_fourcc2str(st->codecpar->codec_tag),
116 st->codecpar->codec_id);
118 /* xWMA shouldn't have extradata. But the WMA codecs require it,
119 * so we provide our own fake extradata.
121 * First, check that there really was no extradata in the header. If
122 * there was, then try to use it, after asking the user to provide a
123 * sample of this unusual file.
125 if (st->codecpar->extradata_size != 0) {
126 /* Surprise, surprise: We *did* get some extradata. No idea
127 * if it will work, but just go on and try it, after asking
128 * the user for a sample.
130 avpriv_request_sample(s, "Unexpected extradata (%d bytes)",
131 st->codecpar->extradata_size);
132 } else if (st->codecpar->codec_id == AV_CODEC_ID_WMAPRO) {
133 if ((ret = ff_alloc_extradata(st->codecpar, 18)) < 0)
136 memset(st->codecpar->extradata, 0, st->codecpar->extradata_size);
137 st->codecpar->extradata[ 0] = st->codecpar->bits_per_coded_sample;
138 st->codecpar->extradata[14] = 224;
140 if ((ret = ff_alloc_extradata(st->codecpar, 6)) < 0)
143 memset(st->codecpar->extradata, 0, st->codecpar->extradata_size);
144 /* setup extradata with our experimentally obtained value */
145 st->codecpar->extradata[4] = 31;
149 if (!st->codecpar->channels) {
150 av_log(s, AV_LOG_WARNING, "Invalid channel count: %d\n",
151 st->codecpar->channels);
152 return AVERROR_INVALIDDATA;
154 if (!st->codecpar->bits_per_coded_sample) {
155 av_log(s, AV_LOG_WARNING, "Invalid bits_per_coded_sample: %d\n",
156 st->codecpar->bits_per_coded_sample);
157 return AVERROR_INVALIDDATA;
160 /* set the sample rate */
161 avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
163 /* parse the remaining RIFF chunks */
165 if (pb->eof_reached) {
169 /* read next chunk tag */
171 size = avio_rl32(pb);
172 if (tag == MKTAG('d', 'a', 't', 'a')) {
173 /* We assume that the data chunk comes last. */
175 } else if (tag == MKTAG('d','p','d','s')) {
176 /* Quoting the MSDN xWMA docs on the dpds chunk: "Contains the
177 * decoded packet cumulative data size array, each element is the
178 * number of bytes accumulated after the corresponding xWMA packet
179 * is decoded in order."
181 * Each packet has size equal to st->codecpar->block_align, which in
182 * all cases I saw so far was always 2230. Thus, we can use the
183 * dpds data to compute a seeking index.
186 /* Error out if there is more than one dpds chunk. */
188 av_log(s, AV_LOG_ERROR, "two dpds chunks present\n");
189 ret = AVERROR_INVALIDDATA;
193 /* Compute the number of entries in the dpds chunk. */
194 if (size & 3) { /* Size should be divisible by four */
195 av_log(s, AV_LOG_WARNING,
196 "dpds chunk size %"PRId64" not divisible by 4\n", size);
198 dpds_table_size = size / 4;
199 if (dpds_table_size == 0 || dpds_table_size >= INT_MAX / 4) {
200 av_log(s, AV_LOG_ERROR,
201 "dpds chunk size %"PRId64" invalid\n", size);
202 return AVERROR_INVALIDDATA;
205 /* Allocate some temporary storage to keep the dpds data around.
206 * for processing later on.
208 dpds_table = av_malloc_array(dpds_table_size, sizeof(uint32_t));
210 return AVERROR(ENOMEM);
213 for (i = 0; i < dpds_table_size; ++i) {
215 ret = AVERROR_INVALIDDATA;
218 dpds_table[i] = avio_rl32(pb);
225 /* Determine overall data length */
227 ret = AVERROR_INVALIDDATA;
231 xwma->data_end = INT64_MAX;
233 xwma->data_end = avio_tell(pb) + size;
236 if (dpds_table && dpds_table_size) {
238 const uint32_t bytes_per_sample
239 = (st->codecpar->channels * st->codecpar->bits_per_coded_sample) >> 3;
241 /* Estimate the duration from the total number of output bytes. */
242 const uint64_t total_decoded_bytes = dpds_table[dpds_table_size - 1];
244 if (!bytes_per_sample) {
245 av_log(s, AV_LOG_ERROR,
246 "Invalid bits_per_coded_sample %d for %d channels\n",
247 st->codecpar->bits_per_coded_sample, st->codecpar->channels);
248 ret = AVERROR_INVALIDDATA;
252 st->duration = total_decoded_bytes / bytes_per_sample;
254 /* Use the dpds data to build a seek table. We can only do this after
255 * we know the offset to the data chunk, as we need that to determine
256 * the actual offset to each input block.
257 * Note: If we allowed ourselves to assume that the data chunk always
258 * follows immediately after the dpds block, we could of course guess
259 * the data block's start offset already while reading the dpds chunk.
260 * I decided against that, just in case other chunks ever are
263 cur_pos = avio_tell(pb);
264 for (i = 0; i < dpds_table_size; ++i) {
265 /* From the number of output bytes that would accumulate in the
266 * output buffer after decoding the first (i+1) packets, we compute
267 * an offset / timestamp pair.
269 av_add_index_entry(st,
270 cur_pos + (i+1) * st->codecpar->block_align, /* pos */
271 dpds_table[i] / bytes_per_sample, /* timestamp */
272 st->codecpar->block_align, /* size */
276 } else if (st->codecpar->bit_rate) {
277 /* No dpds chunk was present (or only an empty one), so estimate
278 * the total duration using the average bits per sample and the
281 st->duration = (size<<3) * st->codecpar->sample_rate / st->codecpar->bit_rate;
290 static int xwma_read_packet(AVFormatContext *s, AVPacket *pkt)
295 XWMAContext *xwma = s->priv_data;
299 left = xwma->data_end - avio_tell(s->pb);
304 /* read a single block; the default block size is 2230. */
305 size = (st->codecpar->block_align > 1) ? st->codecpar->block_align : 2230;
306 size = FFMIN(size, left);
308 ret = av_get_packet(s->pb, pkt, size);
312 pkt->stream_index = 0;
316 AVInputFormat ff_xwma_demuxer = {
318 .long_name = NULL_IF_CONFIG_SMALL("Microsoft xWMA"),
319 .priv_data_size = sizeof(XWMAContext),
320 .read_probe = xwma_probe,
321 .read_header = xwma_read_header,
322 .read_packet = xwma_read_packet,