FFmpeg
hcom.c
Go to the documentation of this file.
1 /*
2  * HCOM demuxer
3  * Copyright (c) 2019 Paul B Mahol
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 "libavutil/intreadwrite.h"
23 #include "libavcodec/internal.h"
24 #include "avformat.h"
25 #include "internal.h"
26 #include "pcm.h"
27 
28 static int hcom_probe(const AVProbeData *p)
29 {
30  if (p->buf_size < 132)
31  return 0;
32  if (!memcmp(p->buf+65, "FSSD", 4) &&
33  !memcmp(p->buf+128, "HCOM", 4))
34  return AVPROBE_SCORE_MAX;
35  return 0;
36 }
37 
38 static int hcom_read_header(AVFormatContext *s)
39 {
40  AVStream *st;
41  unsigned data_size, rsrc_size, huffcount;
42  unsigned compresstype, divisor;
43  unsigned dict_entries;
44  int ret;
45 
46  avio_skip(s->pb, 83);
47  data_size = avio_rb32(s->pb);
48  rsrc_size = avio_rb32(s->pb);
49  avio_skip(s->pb, 128-91+4);
50  huffcount = avio_rb32(s->pb);
51  avio_skip(s->pb, 4);
52  compresstype = avio_rb32(s->pb);
53  if (compresstype > 1)
54  return AVERROR_INVALIDDATA;
55  divisor = avio_rb32(s->pb);
56  if (divisor == 0 || divisor > 4)
57  return AVERROR_INVALIDDATA;
58  dict_entries = avio_rb16(s->pb);
59 
60  st = avformat_new_stream(s, NULL);
61  if (!st)
62  return AVERROR(ENOMEM);
63 
64  st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
65  st->codecpar->channels = 1;
66  st->codecpar->sample_rate = 22050 / divisor;
67  st->codecpar->codec_id = AV_CODEC_ID_HCOM;
68  st->codecpar->bits_per_coded_sample = 8;
69  st->codecpar->block_align = 4;
70 
71  ret = ff_alloc_extradata(st->codecpar, dict_entries * 4 + 7);
72  if (ret < 0)
73  return ret;
74  AV_WB16(st->codecpar->extradata, dict_entries);
75  AV_WB32(st->codecpar->extradata + 2, compresstype);
76  avio_read(s->pb, st->codecpar->extradata + 6, dict_entries * 4);
77  avio_skip(s->pb, 1);
78  st->codecpar->extradata[dict_entries * 4 + 6] = avio_r8(s->pb);
79 
80  avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
81 
82  return 0;
83 }
84 
85 AVInputFormat ff_hcom_demuxer = {
86  .name = "hcom",
87  .long_name = NULL_IF_CONFIG_SMALL("Macintosh HCOM"),
88  .read_probe = hcom_probe,
89  .read_header = hcom_read_header,
90  .read_packet = ff_pcm_read_packet,
91 };
AVCodecParameters::extradata
uint8_t * extradata
Extra binary data needed for initializing the decoder, codec-dependent.
Definition: avcodec.h:3971
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4480
pcm.h
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3953
AV_CODEC_ID_HCOM
@ AV_CODEC_ID_HCOM
Definition: avcodec.h:654
internal.h
AVProbeData::buf_size
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:449
hcom_probe
static int hcom_probe(const AVProbeData *p)
Definition: hcom.c:28
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:458
AVCodecParameters::channels
int channels
Audio only.
Definition: avcodec.h:4063
avio_rb32
unsigned int avio_rb32(AVIOContext *s)
Definition: aviobuf.c:800
AVInputFormat
Definition: avformat.h:640
intreadwrite.h
s
#define s(width, name)
Definition: cbs_vp9.c:257
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:645
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:448
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
AVFormatContext
Format I/O context.
Definition: avformat.h:1342
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1017
NULL
#define NULL
Definition: coverity.c:32
AV_WB16
#define AV_WB16(p, v)
Definition: intreadwrite.h:405
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
ff_hcom_demuxer
AVInputFormat ff_hcom_demuxer
Definition: hcom.c:85
AVCodecParameters::sample_rate
int sample_rate
Audio only.
Definition: avcodec.h:4067
AV_WB32
#define AV_WB32(p, v)
Definition: intreadwrite.h:419
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:188
avpriv_set_pts_info
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:4910
avio_r8
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:638
AVCodecParameters::block_align
int block_align
Audio only.
Definition: avcodec.h:4074
ff_pcm_read_packet
int ff_pcm_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: pcm.c:29
ret
ret
Definition: filter_design.txt:187
AVStream
Stream structure.
Definition: avformat.h:870
avio_rb16
unsigned int avio_rb16(AVIOContext *s)
Definition: aviobuf.c:785
avformat.h
avio_read
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:647
avio_skip
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:331
AVCodecParameters::bits_per_coded_sample
int bits_per_coded_sample
The number of bits per sample in the codedwords.
Definition: avcodec.h:3999
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3957
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
hcom_read_header
static int hcom_read_header(AVFormatContext *s)
Definition: hcom.c:38
ff_alloc_extradata
int ff_alloc_extradata(AVCodecParameters *par, int size)
Allocate extradata with additional AV_INPUT_BUFFER_PADDING_SIZE at end which is always set to 0.
Definition: utils.c:3309
Generated on Wed Aug 24 2022 21:26:42 for FFmpeg by   doxygen 1.8.17