blob: 806f91b6b135e167637c90143a110cfdceb082de
| 1 | /* |
| 2 | * PCM common functions |
| 3 | * Copyright (c) 2003 Fabrice Bellard |
| 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/mathematics.h" |
| 23 | #include "avformat.h" |
| 24 | #include "internal.h" |
| 25 | #include "pcm.h" |
| 26 | |
| 27 | #define RAW_SAMPLES 1024 |
| 28 | |
| 29 | int ff_pcm_read_packet(AVFormatContext *s, AVPacket *pkt) |
| 30 | { |
| 31 | int ret, size; |
| 32 | |
| 33 | size= RAW_SAMPLES*s->streams[0]->codecpar->block_align; |
| 34 | if (size <= 0) |
| 35 | return AVERROR(EINVAL); |
| 36 | |
| 37 | ret= av_get_packet(s->pb, pkt, size); |
| 38 | |
| 39 | pkt->flags &= ~AV_PKT_FLAG_CORRUPT; |
| 40 | pkt->stream_index = 0; |
| 41 | |
| 42 | return ret; |
| 43 | } |
| 44 | |
| 45 | int ff_pcm_read_seek(AVFormatContext *s, |
| 46 | int stream_index, int64_t timestamp, int flags) |
| 47 | { |
| 48 | AVStream *st; |
| 49 | int block_align, byte_rate; |
| 50 | int64_t pos, ret; |
| 51 | |
| 52 | st = s->streams[0]; |
| 53 | |
| 54 | block_align = st->codecpar->block_align ? st->codecpar->block_align : |
| 55 | (av_get_bits_per_sample(st->codecpar->codec_id) * st->codecpar->channels) >> 3; |
| 56 | byte_rate = st->codecpar->bit_rate ? st->codecpar->bit_rate >> 3 : |
| 57 | block_align * st->codecpar->sample_rate; |
| 58 | |
| 59 | if (block_align <= 0 || byte_rate <= 0) |
| 60 | return -1; |
| 61 | if (timestamp < 0) timestamp = 0; |
| 62 | |
| 63 | /* compute the position by aligning it to block_align */ |
| 64 | pos = av_rescale_rnd(timestamp * byte_rate, |
| 65 | st->time_base.num, |
| 66 | st->time_base.den * (int64_t)block_align, |
| 67 | (flags & AVSEEK_FLAG_BACKWARD) ? AV_ROUND_DOWN : AV_ROUND_UP); |
| 68 | pos *= block_align; |
| 69 | |
| 70 | /* recompute exact position */ |
| 71 | st->cur_dts = av_rescale(pos, st->time_base.den, byte_rate * (int64_t)st->time_base.num); |
| 72 | if ((ret = avio_seek(s->pb, pos + s->internal->data_offset, SEEK_SET)) < 0) |
| 73 | return ret; |
| 74 | return 0; |
| 75 | } |
| 76 |