| /* |
| * MIDI Sample Dump Standard format demuxer |
| * Copyright (c) 2017 Paul B Mahol |
| * |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * FFmpeg is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| #include "libavutil/intreadwrite.h" |
| #include "avformat.h" |
| #include "internal.h" |
| |
| typedef struct SDSContext { |
| uint8_t data[120]; |
| int bit_depth; |
| int size; |
| void (*read_block)(const uint8_t *src, uint32_t *dst); |
| } SDSContext; |
| |
| static int sds_probe(const AVProbeData *p) |
| { |
| if (AV_RB32(p->buf) == 0xF07E0001 && p->buf[20] == 0xF7 && |
| p->buf[6] >= 8 && p->buf[6] <= 28) |
| return AVPROBE_SCORE_EXTENSION; |
| return 0; |
| } |
| |
| static void byte2_read(const uint8_t *src, uint32_t *dst) |
| { |
| int i; |
| |
| for (i = 0; i < 120; i += 2) { |
| unsigned sample = ((unsigned)src[i + 0] << 25) + ((unsigned)src[i + 1] << 18); |
| |
| dst[i / 2] = sample; |
| } |
| } |
| |
| static void byte3_read(const uint8_t *src, uint32_t *dst) |
| { |
| int i; |
| |
| for (i = 0; i < 120; i += 3) { |
| unsigned sample; |
| |
| sample = ((unsigned)src[i + 0] << 25) | ((unsigned)src[i + 1] << 18) | ((unsigned)src[i + 2] << 11); |
| dst[i / 3] = sample; |
| } |
| } |
| |
| static void byte4_read(const uint8_t *src, uint32_t *dst) |
| { |
| int i; |
| |
| for (i = 0; i < 120; i += 4) { |
| unsigned sample; |
| |
| sample = ((unsigned)src[i + 0] << 25) | ((unsigned)src[i + 1] << 18) | ((unsigned)src[i + 2] << 11) | ((unsigned)src[i + 3] << 4); |
| dst[i / 4] = sample; |
| } |
| } |
| |
| #define SDS_3BYTE_TO_INT_DECODE(x) (((x) & 0x7F) | (((x) & 0x7F00) >> 1) | (((x) & 0x7F0000) >> 2)) |
| |
| static int sds_read_header(AVFormatContext *ctx) |
| { |
| SDSContext *s = ctx->priv_data; |
| unsigned sample_period; |
| AVIOContext *pb = ctx->pb; |
| AVStream *st; |
| |
| st = avformat_new_stream(ctx, NULL); |
| if (!st) |
| return AVERROR(ENOMEM); |
| |
| avio_skip(pb, 4); |
| avio_skip(pb, 2); |
| |
| s->bit_depth = avio_r8(pb); |
| if (s->bit_depth < 8 || s->bit_depth > 28) |
| return AVERROR_INVALIDDATA; |
| |
| if (s->bit_depth < 14) { |
| s->read_block = byte2_read; |
| s->size = 60 * 4; |
| } else if (s->bit_depth < 21) { |
| s->read_block = byte3_read; |
| s->size = 40 * 4; |
| } else { |
| s->read_block = byte4_read; |
| s->size = 30 * 4; |
| } |
| st->codecpar->codec_id = AV_CODEC_ID_PCM_U32LE; |
| |
| sample_period = avio_rl24(pb); |
| sample_period = SDS_3BYTE_TO_INT_DECODE(sample_period); |
| avio_skip(pb, 11); |
| |
| st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO; |
| st->codecpar->channels = 1; |
| st->codecpar->sample_rate = sample_period ? 1000000000 / sample_period : 16000; |
| st->duration = (avio_size(pb) - 21) / (127) * s->size / 4; |
| |
| avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate); |
| |
| return 0; |
| } |
| |
| static int sds_read_packet(AVFormatContext *ctx, AVPacket *pkt) |
| { |
| SDSContext *s = ctx->priv_data; |
| AVIOContext *pb = ctx->pb; |
| int64_t pos; |
| int ret; |
| |
| if (avio_feof(pb)) |
| return AVERROR_EOF; |
| |
| pos = avio_tell(pb); |
| if (avio_rb16(pb) != 0xF07E) |
| return AVERROR_INVALIDDATA; |
| avio_skip(pb, 3); |
| |
| ret = av_new_packet(pkt, s->size); |
| if (ret < 0) |
| return ret; |
| |
| ret = avio_read(pb, s->data, 120); |
| |
| s->read_block(s->data, (uint32_t *)pkt->data); |
| |
| avio_skip(pb, 1); // checksum |
| if (avio_r8(pb) != 0xF7) |
| return AVERROR_INVALIDDATA; |
| |
| pkt->flags &= ~AV_PKT_FLAG_CORRUPT; |
| pkt->stream_index = 0; |
| pkt->pos = pos; |
| |
| return ret; |
| } |
| |
| AVInputFormat ff_sds_demuxer = { |
| .name = "sds", |
| .long_name = NULL_IF_CONFIG_SMALL("MIDI Sample Dump Standard"), |
| .priv_data_size = sizeof(SDSContext), |
| .read_probe = sds_probe, |
| .read_header = sds_read_header, |
| .read_packet = sds_read_packet, |
| .extensions = "sds", |
| .flags = AVFMT_GENERIC_INDEX, |
| }; |