mirror of https://github.com/FFmpeg/FFmpeg.git
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
55 lines
2.0 KiB
55 lines
2.0 KiB
/* |
|
* PCM common functions |
|
* Copyright (c) 2003 Fabrice Bellard |
|
* |
|
* 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 "avformat.h" |
|
#include "pcm.h" |
|
|
|
int pcm_read_seek(AVFormatContext *s, |
|
int stream_index, int64_t timestamp, int flags) |
|
{ |
|
AVStream *st; |
|
int block_align, byte_rate; |
|
int64_t pos, ret; |
|
|
|
st = s->streams[0]; |
|
|
|
block_align = st->codec->block_align ? st->codec->block_align : |
|
(av_get_bits_per_sample(st->codec->codec_id) * st->codec->channels) >> 3; |
|
byte_rate = st->codec->bit_rate ? st->codec->bit_rate >> 3 : |
|
block_align * st->codec->sample_rate; |
|
|
|
if (block_align <= 0 || byte_rate <= 0) |
|
return -1; |
|
if (timestamp < 0) timestamp = 0; |
|
|
|
/* compute the position by aligning it to block_align */ |
|
pos = av_rescale_rnd(timestamp * byte_rate, |
|
st->time_base.num, |
|
st->time_base.den * (int64_t)block_align, |
|
(flags & AVSEEK_FLAG_BACKWARD) ? AV_ROUND_DOWN : AV_ROUND_UP); |
|
pos *= block_align; |
|
|
|
/* recompute exact position */ |
|
st->cur_dts = av_rescale(pos, st->time_base.den, byte_rate * (int64_t)st->time_base.num); |
|
if ((ret = url_fseek(s->pb, pos + s->data_offset, SEEK_SET)) < 0) |
|
return ret; |
|
return 0; |
|
}
|
|
|