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/*****************************************************************
* gmerlin-avdecoder - a general purpose multimedia decoding library
*
* Copyright (c) 2001 - 2012 Members of the Gmerlin project
* gmerlin-general@lists.sourceforge.net
* http://gmerlin.sourceforge.net
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
* *****************************************************************/
#include <avdec_private.h>
#include <stdlib.h>
#include <stdio.h>
#include <a52dec/a52.h>
/* A52 demuxer */
#define FRAME_SAMPLES 1536 /* 6 * 256 */
#define SYNC_BYTES 3840 /* Maximum possible length of a frame */
typedef struct
{
int64_t frame_count;
int samplerate;
int64_t data_size;
} a52_priv_t;
static int probe_a52(bgav_input_context_t * input)
{
int dummy_flags;
int dummy_srate;
int dummy_brate;
uint8_t test_data[7];
if(bgav_input_get_data(input, test_data, 7) < 7)
return 0;
return !!a52_syncinfo(test_data, &dummy_flags, &dummy_srate, &dummy_brate);
}
static int open_a52(bgav_demuxer_context_t * ctx)
{
int dummy_flags;
int bitrate;
uint8_t test_data[7];
a52_priv_t * priv;
bgav_stream_t * s;
priv = calloc(1, sizeof(*priv));
ctx->priv = priv;
/* Recheck header */
if(bgav_input_get_data(ctx->input, test_data, 7) < 7)
return 0;
if(!a52_syncinfo(test_data, &dummy_flags, &priv->samplerate,
&bitrate))
goto fail;
/* Create track */
ctx->tt = bgav_track_table_create(1);
s = bgav_track_add_audio_stream(ctx->tt->cur, ctx->opt);
s->container_bitrate = bitrate;
/* We just set the fourcc, everything else will be set by the decoder */
s->fourcc = BGAV_MK_FOURCC('.', 'a', 'c', '3');
ctx->data_start = ctx->input->position;
ctx->flags |= BGAV_DEMUXER_HAS_DATA_START;
if(ctx->input->total_bytes)
priv->data_size = ctx->input->total_bytes - ctx->data_start;
/* Packet size will be at least 1024 bytes */
if(ctx->input->flags & BGAV_INPUT_CAN_SEEK_BYTE)
ctx->flags |= BGAV_DEMUXER_CAN_SEEK;
gavl_track_set_duration(ctx->tt->cur->info,
((int64_t)priv->data_size * (int64_t)GAVL_TIME_SCALE) /
(s->container_bitrate / 8));
ctx->index_mode = INDEX_MODE_SIMPLE;
bgav_track_set_format(ctx->tt->cur, "AC3", NULL);
return 1;
fail:
return 0;
}
static int next_packet_a52(bgav_demuxer_context_t * ctx)
{
int dummy_brate, dummy_srate, dummy_flags;
bgav_packet_t * p;
bgav_stream_t * s;
a52_priv_t * priv;
uint8_t test_data[7];
int packet_size, i;
priv = ctx->priv;
s = bgav_track_get_audio_stream(ctx->tt->cur, 0);
p = bgav_stream_get_packet_write(s);
for(i = 0; i < SYNC_BYTES; i++)
{
if(bgav_input_get_data(ctx->input, test_data, 7) < 7)
return 0;
packet_size = a52_syncinfo(test_data, &dummy_flags, &dummy_srate, &dummy_brate);
if(packet_size)
break;
bgav_input_skip(ctx->input, 1);
}
if(!packet_size)
return 0;
p->pts = FRAME_SAMPLES * priv->frame_count;
p->duration = FRAME_SAMPLES;
PACKET_SET_KEYFRAME(p);
p->position = ctx->input->position;
priv->frame_count++;
bgav_packet_alloc(p, packet_size);
p->data_size = bgav_input_read_data(ctx->input, p->data, packet_size);
if(p->data_size < packet_size)
return 0;
bgav_stream_done_packet_write(s, p);
return 1;
}
static void seek_a52(bgav_demuxer_context_t * ctx, int64_t time, int scale)
{
int64_t file_position;
a52_priv_t * priv;
int64_t t;
bgav_stream_t * s;
priv = ctx->priv;
s = bgav_track_get_audio_stream(ctx->tt->cur, 0);
file_position = (time * (s->container_bitrate / 8)) /
scale;
/* Calculate the time before we add the start offset */
t = ((int64_t)file_position * scale) /
(s->container_bitrate / 8);
STREAM_SET_SYNC(s, gavl_time_rescale(scale, priv->samplerate, t));
priv->frame_count = STREAM_GET_SYNC(s) / FRAME_SAMPLES;
file_position += ctx->data_start;
bgav_input_seek(ctx->input, file_position, SEEK_SET);
}
static int select_track_a52(bgav_demuxer_context_t * ctx, int track)
{
a52_priv_t * priv;
priv = ctx->priv;
priv->frame_count = 0;
return 1;
}
static void close_a52(bgav_demuxer_context_t * ctx)
{
a52_priv_t * priv;
priv = ctx->priv;
free(priv);
}
const bgav_demuxer_t bgav_demuxer_a52 =
{
.probe = probe_a52,
.open = open_a52,
.select_track = select_track_a52,
.next_packet = next_packet_a52,
.seek = seek_a52,
.close = close_a52
};
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