From 87c57d807fa198b97587bbf211b8d375f925c737 Mon Sep 17 00:00:00 2001 From: Justin Ruggles Date: Fri, 28 Oct 2011 00:07:32 -0400 Subject: Create separate functions for the raw GSM demuxer. Put the new raw GSM demuxer in its own file. Fixes raw GSM demuxing. --- libavformat/gsmdec.c | 135 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 135 insertions(+) create mode 100644 libavformat/gsmdec.c (limited to 'libavformat/gsmdec.c') diff --git a/libavformat/gsmdec.c b/libavformat/gsmdec.c new file mode 100644 index 0000000000..291e2c56aa --- /dev/null +++ b/libavformat/gsmdec.c @@ -0,0 +1,135 @@ +/* + * RAW GSM demuxer + * Copyright (c) 2011 Justin Ruggles + * + * This file is part of Libav. + * + * Libav 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. + * + * Libav 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 Libav; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include "libavutil/mathematics.h" +#include "libavutil/opt.h" +#include "avformat.h" + +#define GSM_BLOCK_SIZE 33 +#define GSM_BLOCK_SAMPLES 160 +#define GSM_SAMPLE_RATE 8000 + +typedef struct { + AVClass *class; + int sample_rate; +} GSMDemuxerContext; + +static int gsm_read_packet(AVFormatContext *s, AVPacket *pkt) +{ + int ret, size; + + size = GSM_BLOCK_SIZE * 32; + + if (av_new_packet(pkt, size) < 0) + return AVERROR(ENOMEM); + + pkt->pos = avio_tell(s->pb); + pkt->stream_index = 0; + + ret = av_get_packet(s->pb, pkt, size); + if (ret < GSM_BLOCK_SIZE) { + av_free_packet(pkt); + return ret < 0 ? ret : AVERROR(EIO); + } + pkt->size = ret; + pkt->duration = ret / GSM_BLOCK_SIZE; + pkt->pts = pkt->pos / GSM_BLOCK_SIZE; + + return 0; +} + +static int gsm_read_header(AVFormatContext *s, AVFormatParameters *ap) +{ + GSMDemuxerContext *c = s->priv_data; + AVStream *st = avformat_new_stream(s, NULL); + if (!st) + return AVERROR(ENOMEM); + + st->codec->codec_type = AVMEDIA_TYPE_AUDIO; + st->codec->codec_id = s->iformat->value; + st->codec->channels = 1; + st->codec->sample_rate = c->sample_rate; + st->codec->block_align = GSM_BLOCK_SIZE; + st->codec->bit_rate = GSM_BLOCK_SIZE * 8 * c->sample_rate / GSM_BLOCK_SAMPLES; + + av_set_pts_info(st, 64, GSM_BLOCK_SAMPLES, GSM_SAMPLE_RATE); + + return 0; +} + +static int gsm_read_seek2(AVFormatContext *s, int stream_index, int64_t min_ts, + int64_t ts, int64_t max_ts, int flags) +{ + GSMDemuxerContext *c = s->priv_data; + + /* convert timestamps to file positions */ + if (!(flags & AVSEEK_FLAG_BYTE)) { + if (stream_index < 0) { + AVRational bitrate_q = { GSM_BLOCK_SAMPLES, c->sample_rate * GSM_BLOCK_SIZE }; + ts = av_rescale_q(ts, AV_TIME_BASE_Q, bitrate_q); + min_ts = av_rescale_q(min_ts, AV_TIME_BASE_Q, bitrate_q); + max_ts = av_rescale_q(max_ts, AV_TIME_BASE_Q, bitrate_q); + } else { + ts *= GSM_BLOCK_SIZE; + min_ts *= GSM_BLOCK_SIZE; + max_ts *= GSM_BLOCK_SIZE; + } + } + /* round to nearest block boundary */ + ts = (ts + GSM_BLOCK_SIZE / 2) / GSM_BLOCK_SIZE * GSM_BLOCK_SIZE; + ts = FFMAX(0, ts); + + /* handle min/max */ + while (ts < min_ts) + ts += GSM_BLOCK_SIZE; + while (ts > max_ts) + ts -= GSM_BLOCK_SIZE; + if (ts < min_ts || ts > max_ts) + return -1; + + return avio_seek(s->pb, ts, SEEK_SET); +} + +static const AVOption options[] = { + { "sample_rate", "", offsetof(GSMDemuxerContext, sample_rate), + AV_OPT_TYPE_INT, {.dbl = GSM_SAMPLE_RATE}, 1, INT_MAX / GSM_BLOCK_SIZE, + AV_OPT_FLAG_DECODING_PARAM }, + { NULL }, +}; + +static const AVClass class = { + .class_name = "gsm demuxer", + .item_name = av_default_item_name, + .option = options, + .version = LIBAVUTIL_VERSION_INT, +}; + +AVInputFormat ff_gsm_demuxer = { + .name = "gsm", + .long_name = NULL_IF_CONFIG_SMALL("raw GSM"), + .priv_data_size = sizeof(GSMDemuxerContext), + .read_header = gsm_read_header, + .read_packet = gsm_read_packet, + .read_seek2 = gsm_read_seek2, + .extensions = "gsm", + .value = CODEC_ID_GSM, + .priv_class = &class, +}; -- cgit v1.2.3