FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/dfpwmdec.c
Date: 2022-10-02 18:56:10
Exec Total Coverage
Lines: 41 45 91.1%
Branches: 23 28 82.1%

Line Branch Exec Source
1 /*
2 * DFPWM decoder
3 * Copyright (c) 2022 Jack Bruienne
4 * Copyright (c) 2012, 2016 Ben "GreaseMonkey" Russell
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 /**
24 * @file
25 * DFPWM1a decoder
26 */
27
28 #include "libavutil/internal.h"
29 #include "avcodec.h"
30 #include "codec_id.h"
31 #include "codec_internal.h"
32 #include "decode.h"
33
34 typedef struct {
35 int fq, q, s, lt;
36 } DFPWMState;
37
38 // DFPWM codec from https://github.com/ChenThread/dfpwm/blob/master/1a/
39 // Licensed in the public domain
40
41 6 static void au_decompress(DFPWMState *state, int fs, int len,
42 uint8_t *outbuf, const uint8_t *inbuf)
43 {
44 unsigned d;
45
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5519 for (int i = 0; i < len; i++) {
46 // get bits
47 5513 d = *(inbuf++);
48
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49617 for (int j = 0; j < 8; j++) {
49 int nq, lq, st, ns, ov;
50 // set target
51
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44104 int t = ((d&1) ? 127 : -128);
52 44104 d >>= 1;
53
54 // adjust charge
55 44104 nq = state->q + ((state->s * (t-state->q) + 512)>>10);
56
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44104 if(nq == state->q && nq != t)
57
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1 nq += (t == 127 ? 1 : -1);
58 44104 lq = state->q;
59 44104 state->q = nq;
60
61 // adjust strength
62
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44104 st = (t != state->lt ? 0 : 1023);
63 44104 ns = state->s;
64
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44104 if(ns != st)
65
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44103 ns += (st != 0 ? 1 : -1);
66
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44104 if(ns < 8) ns = 8;
67 44104 state->s = ns;
68
69 // FILTER: perform antijerk
70
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44104 ov = (t != state->lt ? (nq+lq+1)>>1 : nq);
71
72 // FILTER: perform LPF
73 44104 state->fq += ((fs*(ov-state->fq) + 0x80)>>8);
74 44104 ov = state->fq;
75
76 // output sample
77 44104 *(outbuf++) = ov + 128;
78
79 44104 state->lt = t;
80 }
81 }
82 6 }
83
84 2 static av_cold int dfpwm_dec_init(struct AVCodecContext *ctx)
85 {
86 2 DFPWMState *state = ctx->priv_data;
87
88 2 state->fq = 0;
89 2 state->q = 0;
90 2 state->s = 0;
91 2 state->lt = -128;
92
93 2 ctx->sample_fmt = AV_SAMPLE_FMT_U8;
94 2 ctx->bits_per_raw_sample = 8;
95
96 2 return 0;
97 }
98
99 6 static int dfpwm_dec_frame(struct AVCodecContext *ctx, AVFrame *frame,
100 int *got_frame, struct AVPacket *packet)
101 {
102 6 DFPWMState *state = ctx->priv_data;
103 int ret;
104
105
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6 if (packet->size * 8LL % ctx->ch_layout.nb_channels)
106 return AVERROR_PATCHWELCOME;
107
108 6 frame->nb_samples = packet->size * 8LL / ctx->ch_layout.nb_channels;
109
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6 if (frame->nb_samples <= 0) {
110 av_log(ctx, AV_LOG_ERROR, "invalid number of samples in packet\n");
111 return AVERROR_INVALIDDATA;
112 }
113
114
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6 if ((ret = ff_get_buffer(ctx, frame, 0)) < 0)
115 return ret;
116
117 6 au_decompress(state, 140, packet->size, frame->data[0], packet->data);
118
119 6 *got_frame = 1;
120 6 return packet->size;
121 }
122
123 const FFCodec ff_dfpwm_decoder = {
124 .p.name = "dfpwm",
125 CODEC_LONG_NAME("DFPWM1a audio"),
126 .p.type = AVMEDIA_TYPE_AUDIO,
127 .p.id = AV_CODEC_ID_DFPWM,
128 .priv_data_size = sizeof(DFPWMState),
129 .init = dfpwm_dec_init,
130 FF_CODEC_DECODE_CB(dfpwm_dec_frame),
131 .p.capabilities = AV_CODEC_CAP_DR1,
132 };
133