4 * Copyright (C) 2020 Zane van Iperen (zane@zanevaniperen.com)
6 * This file is part of FFmpeg.
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.
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.
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
25 #include "libavutil/internal.h"
26 #include "libavutil/intreadwrite.h"
28 #define APM_FILE_HEADER_SIZE 20
29 #define APM_VS12_CHUNK_SIZE 76
30 #define APM_MAX_READ_SIZE 4096
32 #define APM_TAG_CODEC 0x2000
33 #define APM_TAG_VS12 MKTAG('v', 's', '1', '2')
34 #define APM_TAG_DATA MKTAG('D', 'A', 'T', 'A')
36 typedef struct APMState {
46 typedef struct APMVS12Chunk {
56 static void apm_parse_vs12(APMVS12Chunk *vs12, const uint8_t *buf)
58 vs12->magic = AV_RL32(buf + 0);
59 vs12->file_size = AV_RL32(buf + 4);
60 vs12->data_size = AV_RL32(buf + 8);
61 vs12->unk1 = AV_RL32(buf + 12);
62 vs12->unk2 = AV_RL32(buf + 16);
64 vs12->state.has_saved = AV_RL32(buf + 20);
65 vs12->state.predictor_r = AV_RL32(buf + 24);
66 vs12->state.step_index_r = AV_RL32(buf + 28);
67 vs12->state.saved_r = AV_RL32(buf + 32);
68 vs12->state.predictor_l = AV_RL32(buf + 36);
69 vs12->state.step_index_l = AV_RL32(buf + 40);
70 vs12->state.saved_l = AV_RL32(buf + 44);
72 for (int i = 0; i < FF_ARRAY_ELEMS(vs12->pad); i++)
73 vs12->pad[i] = AV_RL32(buf + 48 + (i * 4));
76 static int apm_probe(const AVProbeData *p)
78 if (AV_RL16(p->buf) != APM_TAG_CODEC)
81 if (p->buf_size < 100)
84 if (AV_RL32(p->buf + 20) != APM_TAG_VS12)
87 if (AV_RL32(p->buf + 96) != APM_TAG_DATA)
90 return AVPROBE_SCORE_MAX - 1;
93 static int apm_read_header(AVFormatContext *s)
98 uint8_t buf[APM_VS12_CHUNK_SIZE];
100 if (!(st = avformat_new_stream(s, NULL)))
101 return AVERROR(ENOMEM);
103 /* The header starts with a WAVEFORMATEX */
104 if ((ret = ff_get_wav_header(s, s->pb, st->codecpar, APM_FILE_HEADER_SIZE, 0)) < 0)
107 if (st->codecpar->bits_per_coded_sample != 4)
108 return AVERROR_INVALIDDATA;
110 if (st->codecpar->codec_tag != APM_TAG_CODEC)
111 return AVERROR_INVALIDDATA;
113 /* ff_get_wav_header() does most of the work, but we need to fix a few things. */
114 st->codecpar->codec_id = AV_CODEC_ID_ADPCM_IMA_APM;
115 st->codecpar->codec_tag = 0;
117 if (st->codecpar->channels == 2)
118 st->codecpar->channel_layout = AV_CH_LAYOUT_STEREO;
119 else if (st->codecpar->channels == 1)
120 st->codecpar->channel_layout = AV_CH_LAYOUT_MONO;
122 return AVERROR_INVALIDDATA;
124 st->codecpar->format = AV_SAMPLE_FMT_S16;
125 st->codecpar->bits_per_raw_sample = 16;
126 st->codecpar->bit_rate = st->codecpar->channels *
127 st->codecpar->sample_rate *
128 st->codecpar->bits_per_coded_sample;
130 if ((ret = avio_read(s->pb, buf, APM_VS12_CHUNK_SIZE)) < 0)
132 else if (ret != APM_VS12_CHUNK_SIZE)
135 apm_parse_vs12(&vs12, buf);
137 if (vs12.magic != APM_TAG_VS12) {
138 return AVERROR_INVALIDDATA;
141 if (vs12.state.has_saved) {
142 avpriv_request_sample(s, "Saved Samples");
143 return AVERROR_PATCHWELCOME;
146 if (avio_rl32(s->pb) != APM_TAG_DATA)
147 return AVERROR_INVALIDDATA;
149 if ((ret = ff_alloc_extradata(st->codecpar, 16)) < 0)
152 AV_WL32(st->codecpar->extradata + 0, vs12.state.predictor_l);
153 AV_WL32(st->codecpar->extradata + 4, vs12.state.step_index_l);
154 AV_WL32(st->codecpar->extradata + 8, vs12.state.predictor_r);
155 AV_WL32(st->codecpar->extradata + 12, vs12.state.step_index_r);
157 avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
159 st->duration = vs12.data_size *
160 (8 / st->codecpar->bits_per_coded_sample) /
161 st->codecpar->channels;
165 static int apm_read_packet(AVFormatContext *s, AVPacket *pkt)
168 AVCodecParameters *par = s->streams[0]->codecpar;
171 * For future reference: if files with the `has_saved` field set ever
172 * surface, `saved_l`, and `saved_r` will each contain 8 "saved" samples
173 * that should be sent to the decoder before the actual data.
176 if ((ret = av_get_packet(s->pb, pkt, APM_MAX_READ_SIZE)) < 0)
179 pkt->flags &= ~AV_PKT_FLAG_CORRUPT;
180 pkt->stream_index = 0;
181 pkt->duration = ret * (8 / par->bits_per_coded_sample) / par->channels;
186 AVInputFormat ff_apm_demuxer = {
188 .long_name = NULL_IF_CONFIG_SMALL("Ubisoft Rayman 2 APM"),
189 .read_probe = apm_probe,
190 .read_header = apm_read_header,
191 .read_packet = apm_read_packet