FFmpeg
bmvaudio.c
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1 /*
2  * Discworld II BMV audio decoder
3  * Copyright (c) 2011 Konstantin Shishkov
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 
23 #include "libavutil/common.h"
24 
25 #include "avcodec.h"
26 #include "codec_internal.h"
27 #include "decode.h"
28 
29 static const int bmv_aud_mults[16] = {
30  16512, 8256, 4128, 2064, 1032, 516, 258, 192, 129, 88, 64, 56, 48, 40, 36, 32
31 };
32 
34 {
38 
39  return 0;
40 }
41 
43  int *got_frame_ptr, AVPacket *avpkt)
44 {
45  const uint8_t *buf = avpkt->data;
46  int buf_size = avpkt->size;
47  int blocks = 0, total_blocks, i;
48  int ret;
49  int16_t *output_samples;
50  int scale[2];
51 
52  total_blocks = *buf++;
53  if (buf_size < total_blocks * 65 + 1) {
54  av_log(avctx, AV_LOG_ERROR, "expected %d bytes, got %d\n",
55  total_blocks * 65 + 1, buf_size);
56  return AVERROR_INVALIDDATA;
57  }
58 
59  /* get output buffer */
60  frame->nb_samples = total_blocks * 32;
61  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
62  return ret;
63  output_samples = (int16_t *)frame->data[0];
64 
65  for (blocks = 0; blocks < total_blocks; blocks++) {
66  uint8_t code = *buf++;
67  code = (code >> 1) | (code << 7);
68  scale[0] = bmv_aud_mults[code & 0xF];
69  scale[1] = bmv_aud_mults[code >> 4];
70  for (i = 0; i < 32; i++) {
71  *output_samples++ = av_clip_int16((scale[0] * (int8_t)*buf++) >> 5);
72  *output_samples++ = av_clip_int16((scale[1] * (int8_t)*buf++) >> 5);
73  }
74  }
75 
76  *got_frame_ptr = 1;
77 
78  return buf_size;
79 }
80 
82  .p.name = "bmv_audio",
83  CODEC_LONG_NAME("Discworld II BMV audio"),
84  .p.type = AVMEDIA_TYPE_AUDIO,
85  .p.id = AV_CODEC_ID_BMV_AUDIO,
86  .init = bmv_aud_decode_init,
88  .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF,
89 };
AV_CHANNEL_LAYOUT_STEREO
#define AV_CHANNEL_LAYOUT_STEREO
Definition: channel_layout.h:389
bmv_aud_decode_init
static av_cold int bmv_aud_decode_init(AVCodecContext *avctx)
Definition: bmvaudio.c:33
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:340
AVPacket::data
uint8_t * data
Definition: packet.h:522
FFCodec
Definition: codec_internal.h:127
AVFrame::data
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:361
FFCodec::p
AVCodec p
The public AVCodec.
Definition: codec_internal.h:131
AVCodecContext::ch_layout
AVChannelLayout ch_layout
Audio channel layout.
Definition: avcodec.h:2111
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
av_cold
#define av_cold
Definition: attributes.h:90
FF_CODEC_DECODE_CB
#define FF_CODEC_DECODE_CB(func)
Definition: codec_internal.h:306
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
decode.h
CODEC_LONG_NAME
#define CODEC_LONG_NAME(str)
Definition: codec_internal.h:272
frame
static AVFrame * frame
Definition: demux_decode.c:54
av_clip_int16
#define av_clip_int16
Definition: common.h:113
AV_CODEC_CAP_CHANNEL_CONF
#define AV_CODEC_CAP_CHANNEL_CONF
Codec should fill in channel configuration and samplerate instead of container.
Definition: codec.h:106
ff_get_buffer
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: decode.c:1618
AV_CODEC_CAP_DR1
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() or get_encode_buffer() for allocating buffers and supports custom allocators.
Definition: codec.h:52
AVPacket::size
int size
Definition: packet.h:523
scale
static void scale(int *out, const int *in, const int w, const int h, const int shift)
Definition: vvc_intra.c:292
AVChannelLayout
An AVChannelLayout holds information about the channel layout of audio data.
Definition: channel_layout.h:313
codec_internal.h
for
for(k=2;k<=8;++k)
Definition: h264pred_template.c:425
AVCodecContext::sample_fmt
enum AVSampleFormat sample_fmt
audio sample format
Definition: avcodec.h:1084
AVFrame::nb_samples
int nb_samples
number of audio samples (per channel) described by this frame
Definition: frame.h:420
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:255
code
and forward the test the status of outputs and forward it to the corresponding return FFERROR_NOT_READY If the filters stores internally one or a few frame for some it can consider them to be part of the FIFO and delay acknowledging a status change accordingly Example code
Definition: filter_design.txt:178
common.h
AV_CODEC_ID_BMV_AUDIO
@ AV_CODEC_ID_BMV_AUDIO
Definition: codec_id.h:499
AV_SAMPLE_FMT_S16
@ AV_SAMPLE_FMT_S16
signed 16 bits
Definition: samplefmt.h:58
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:194
avcodec.h
bmv_aud_decode_frame
static int bmv_aud_decode_frame(AVCodecContext *avctx, AVFrame *frame, int *got_frame_ptr, AVPacket *avpkt)
Definition: bmvaudio.c:42
ret
ret
Definition: filter_design.txt:187
bmv_aud_mults
static const int bmv_aud_mults[16]
Definition: bmvaudio.c:29
ff_bmv_audio_decoder
const FFCodec ff_bmv_audio_decoder
Definition: bmvaudio.c:81
AVCodecContext
main external API structure.
Definition: avcodec.h:445
channel_layout.h
av_channel_layout_uninit
void av_channel_layout_uninit(AVChannelLayout *channel_layout)
Free any allocated data in the channel layout and reset the channel count to 0.
Definition: channel_layout.c:662
AVPacket
This structure stores compressed data.
Definition: packet.h:499
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:27
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61