FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
xwma.c
Go to the documentation of this file.
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 XWMAContext {
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 
45 {
46  int64_t size;
47  int ret = 0;
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, 0);
79  if (ret < 0)
80  return ret;
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  if (ff_alloc_extradata(st->codec, 6))
108  return AVERROR(ENOMEM);
109 
110  memset(st->codec->extradata, 0, st->codec->extradata_size);
111  /* setup extradata with our experimentally obtained value */
112  st->codec->extradata[4] = 31;
113  }
114  }
115 
116  if (!st->codec->channels) {
117  av_log(s, AV_LOG_WARNING, "Invalid channel count: %d\n",
118  st->codec->channels);
119  return AVERROR_INVALIDDATA;
120  }
121  if (!st->codec->bits_per_coded_sample) {
122  av_log(s, AV_LOG_WARNING, "Invalid bits_per_coded_sample: %d\n",
124  return AVERROR_INVALIDDATA;
125  }
126 
127  /* set the sample rate */
128  avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
129 
130  /* parse the remaining RIFF chunks */
131  for (;;) {
132  if (pb->eof_reached) {
133  ret = AVERROR_EOF;
134  goto fail;
135  }
136  /* read next chunk tag */
137  tag = avio_rl32(pb);
138  size = avio_rl32(pb);
139  if (tag == MKTAG('d', 'a', 't', 'a')) {
140  /* We assume that the data chunk comes last. */
141  break;
142  } else if (tag == MKTAG('d','p','d','s')) {
143  /* Quoting the MSDN xWMA docs on the dpds chunk: "Contains the
144  * decoded packet cumulative data size array, each element is the
145  * number of bytes accumulated after the corresponding xWMA packet
146  * is decoded in order."
147  *
148  * Each packet has size equal to st->codec->block_align, which in
149  * all cases I saw so far was always 2230. Thus, we can use the
150  * dpds data to compute a seeking index.
151  */
152 
153  /* Error out if there is more than one dpds chunk. */
154  if (dpds_table) {
155  av_log(s, AV_LOG_ERROR, "two dpds chunks present\n");
156  ret = AVERROR_INVALIDDATA;
157  goto fail;
158  }
159 
160  /* Compute the number of entries in the dpds chunk. */
161  if (size & 3) { /* Size should be divisible by four */
163  "dpds chunk size %"PRId64" not divisible by 4\n", size);
164  }
165  dpds_table_size = size / 4;
166  if (dpds_table_size == 0 || dpds_table_size >= INT_MAX / 4) {
167  av_log(s, AV_LOG_ERROR,
168  "dpds chunk size %"PRId64" invalid\n", size);
169  return AVERROR_INVALIDDATA;
170  }
171 
172  /* Allocate some temporary storage to keep the dpds data around.
173  * for processing later on.
174  */
175  dpds_table = av_malloc_array(dpds_table_size, sizeof(uint32_t));
176  if (!dpds_table) {
177  return AVERROR(ENOMEM);
178  }
179 
180  for (i = 0; i < dpds_table_size; ++i) {
181  dpds_table[i] = avio_rl32(pb);
182  size -= 4;
183  }
184  }
185  avio_skip(pb, size);
186  }
187 
188  /* Determine overall data length */
189  if (size < 0) {
190  ret = AVERROR_INVALIDDATA;
191  goto fail;
192  }
193  if (!size) {
194  xwma->data_end = INT64_MAX;
195  } else
196  xwma->data_end = avio_tell(pb) + size;
197 
198 
199  if (dpds_table && dpds_table_size) {
200  int64_t cur_pos;
201  const uint32_t bytes_per_sample
202  = (st->codec->channels * st->codec->bits_per_coded_sample) >> 3;
203 
204  /* Estimate the duration from the total number of output bytes. */
205  const uint64_t total_decoded_bytes = dpds_table[dpds_table_size - 1];
206 
207  if (!bytes_per_sample) {
208  av_log(s, AV_LOG_ERROR,
209  "Invalid bits_per_coded_sample %d for %d channels\n",
211  ret = AVERROR_INVALIDDATA;
212  goto fail;
213  }
214 
215  st->duration = total_decoded_bytes / bytes_per_sample;
216 
217  /* Use the dpds data to build a seek table. We can only do this after
218  * we know the offset to the data chunk, as we need that to determine
219  * the actual offset to each input block.
220  * Note: If we allowed ourselves to assume that the data chunk always
221  * follows immediately after the dpds block, we could of course guess
222  * the data block's start offset already while reading the dpds chunk.
223  * I decided against that, just in case other chunks ever are
224  * discovered.
225  */
226  cur_pos = avio_tell(pb);
227  for (i = 0; i < dpds_table_size; ++i) {
228  /* From the number of output bytes that would accumulate in the
229  * output buffer after decoding the first (i+1) packets, we compute
230  * an offset / timestamp pair.
231  */
233  cur_pos + (i+1) * st->codec->block_align, /* pos */
234  dpds_table[i] / bytes_per_sample, /* timestamp */
235  st->codec->block_align, /* size */
236  0, /* duration */
238  }
239  } else if (st->codec->bit_rate) {
240  /* No dpds chunk was present (or only an empty one), so estimate
241  * the total duration using the average bits per sample and the
242  * total data length.
243  */
244  st->duration = (size<<3) * st->codec->sample_rate / st->codec->bit_rate;
245  }
246 
247 fail:
248  av_free(dpds_table);
249 
250  return ret;
251 }
252 
254 {
255  int ret, size;
256  int64_t left;
257  AVStream *st;
258  XWMAContext *xwma = s->priv_data;
259 
260  st = s->streams[0];
261 
262  left = xwma->data_end - avio_tell(s->pb);
263  if (left <= 0) {
264  return AVERROR_EOF;
265  }
266 
267  /* read a single block; the default block size is 2230. */
268  size = (st->codec->block_align > 1) ? st->codec->block_align : 2230;
269  size = FFMIN(size, left);
270 
271  ret = av_get_packet(s->pb, pkt, size);
272  if (ret < 0)
273  return ret;
274 
275  pkt->stream_index = 0;
276  return ret;
277 }
278 
280  .name = "xwma",
281  .long_name = NULL_IF_CONFIG_SMALL("Microsoft xWMA"),
282  .priv_data_size = sizeof(XWMAContext),
286 };
#define NULL
Definition: coverity.c:32
const char * s
Definition: avisynth_c.h:631
Bytestream IO Context.
Definition: avio.h:111
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
int av_add_index_entry(AVStream *st, int64_t pos, int64_t timestamp, int size, int distance, int flags)
Add an index entry into a sorted list.
Definition: utils.c:1742
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: utils.c:4006
static int xwma_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: xwma.c:253
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:276
int ff_get_wav_header(AVIOContext *pb, AVCodecContext *codec, int size, int big_endian)
Definition: riffdec.c:84
static AVPacket pkt
int block_align
number of bytes per packet if constant and known or 0 Used by some WAV based audio codecs...
Definition: avcodec.h:2022
Format I/O context.
Definition: avformat.h:1272
void void avpriv_request_sample(void *avc, const char *msg,...) av_printf_format(2
Log a generic warning message about a missing feature.
int64_t data_end
Definition: xwma.c:34
enum AVStreamParseType need_parsing
Definition: avformat.h:1035
uint8_t * extradata
some codecs need / can use extradata like Huffman tables.
Definition: avcodec.h:1355
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:3672
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1340
uint32_t tag
Definition: movenc.c:1333
#define AVERROR_EOF
End of file.
Definition: error.h:55
int av_get_packet(AVIOContext *s, AVPacket *pkt, int size)
Allocate and read the payload of a packet and initialize its fields with default values.
Definition: utils.c:241
ptrdiff_t size
Definition: opengl_enc.c:101
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:365
int bits_per_coded_sample
bits per sample/pixel from the demuxer (needed for huffyuv).
Definition: avcodec.h:2720
#define av_log(a,...)
static int xwma_read_header(AVFormatContext *s)
Definition: xwma.c:44
#define AVINDEX_KEYFRAME
Definition: avformat.h:791
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
AVInputFormat ff_xwma_demuxer
Definition: xwma.c:279
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:658
#define AVERROR(e)
Definition: error.h:43
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:175
static int xwma_probe(AVProbeData *p)
Definition: xwma.c:37
AVCodecContext * codec
Codec context associated with this stream.
Definition: avformat.h:861
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:450
int bit_rate
the average bitrate
Definition: avcodec.h:1305
#define FFMIN(a, b)
Definition: common.h:66
static int read_probe(AVProbeData *pd)
Definition: jvdec.c:55
ret
Definition: avfilter.c:974
internal header for RIFF based (de)muxers do NOT include this in end user applications ...
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:620
Stream structure.
Definition: avformat.h:842
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_reading.c:42
enum AVCodecID codec_id
Definition: avcodec.h:1258
int sample_rate
samples per second
Definition: avcodec.h:1985
AVIOContext * pb
I/O context.
Definition: avformat.h:1314
unsigned int codec_tag
fourcc (LSB first, so "ABCD" -> ('D'<<24) + ('C'<<16) + ('B'<<8) + 'A').
Definition: avcodec.h:1273
int ff_alloc_extradata(AVCodecContext *avctx, int size)
Allocate extradata with additional FF_INPUT_BUFFER_PADDING_SIZE at end which is always set to 0...
Definition: utils.c:2864
int extradata_size
Definition: avcodec.h:1356
This structure contains the data a format has to probe a file.
Definition: avformat.h:448
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:901
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:460
Main libavformat public API header.
#define av_free(p)
int eof_reached
true if eof reached
Definition: avio.h:139
int channels
number of audio channels
Definition: avcodec.h:1986
void * priv_data
Format private data.
Definition: avformat.h:1300
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:628
#define av_malloc_array(a, b)
int stream_index
Definition: avcodec.h:1164
#define MKTAG(a, b, c, d)
Definition: common.h:315
This structure stores compressed data.
Definition: avcodec.h:1139