mirror of https://github.com/FFmpeg/FFmpeg.git
Patch by Anssi Hannula, anssi d hannula a iki d fi Originally committed as revision 25804 to svn://svn.ffmpeg.org/ffmpeg/trunkoldabi
parent
b7be04f3c0
commit
3b39e2739f
6 changed files with 241 additions and 3 deletions
@ -0,0 +1,236 @@ |
||||
/*
|
||||
* IEC 61937 demuxer |
||||
* Copyright (c) 2010 Anssi Hannula <anssi.hannula at iki.fi> |
||||
* |
||||
* 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 |
||||
*/ |
||||
|
||||
/**
|
||||
* @file |
||||
* IEC 61937 demuxer, used for compressed data in S/PDIF |
||||
* @author Anssi Hannula |
||||
*/ |
||||
|
||||
#include "avformat.h" |
||||
#include "spdif.h" |
||||
#include "libavcodec/ac3.h" |
||||
#include "libavcodec/aacadtsdec.h" |
||||
|
||||
static int spdif_get_offset_and_codec(AVFormatContext *s, |
||||
enum IEC958DataType data_type, |
||||
const char *buf, int *offset, |
||||
enum CodecID *codec) |
||||
{ |
||||
AACADTSHeaderInfo aac_hdr; |
||||
GetBitContext gbc; |
||||
|
||||
switch (data_type & 0xff) { |
||||
case IEC958_AC3: |
||||
*offset = AC3_FRAME_SIZE << 2; |
||||
*codec = CODEC_ID_AC3; |
||||
break; |
||||
case IEC958_MPEG1_LAYER1: |
||||
*offset = spdif_mpeg_pkt_offset[1][0]; |
||||
*codec = CODEC_ID_MP1; |
||||
break; |
||||
case IEC958_MPEG1_LAYER23: |
||||
*offset = spdif_mpeg_pkt_offset[1][0]; |
||||
*codec = CODEC_ID_MP3; |
||||
break; |
||||
case IEC958_MPEG2_EXT: |
||||
*offset = 4608; |
||||
*codec = CODEC_ID_MP3; |
||||
break; |
||||
case IEC958_MPEG2_AAC: |
||||
init_get_bits(&gbc, buf, AAC_ADTS_HEADER_SIZE * 8); |
||||
if (ff_aac_parse_header(&gbc, &aac_hdr)) { |
||||
if (s) /* be silent during a probe */ |
||||
av_log(s, AV_LOG_ERROR, "Invalid AAC packet in IEC 61937\n"); |
||||
return AVERROR_INVALIDDATA; |
||||
} |
||||
*offset = aac_hdr.samples << 2; |
||||
*codec = CODEC_ID_AAC; |
||||
break; |
||||
case IEC958_MPEG2_LAYER1_LSF: |
||||
*offset = spdif_mpeg_pkt_offset[0][0]; |
||||
*codec = CODEC_ID_MP1; |
||||
break; |
||||
case IEC958_MPEG2_LAYER2_LSF: |
||||
*offset = spdif_mpeg_pkt_offset[0][1]; |
||||
*codec = CODEC_ID_MP2; |
||||
break; |
||||
case IEC958_MPEG2_LAYER3_LSF: |
||||
*offset = spdif_mpeg_pkt_offset[0][2]; |
||||
*codec = CODEC_ID_MP3; |
||||
break; |
||||
case IEC958_DTS1: |
||||
*offset = 2048; |
||||
*codec = CODEC_ID_DTS; |
||||
break; |
||||
case IEC958_DTS2: |
||||
*offset = 4096; |
||||
*codec = CODEC_ID_DTS; |
||||
break; |
||||
case IEC958_DTS3: |
||||
*offset = 8192; |
||||
*codec = CODEC_ID_DTS; |
||||
break; |
||||
default: |
||||
if (s) { /* be silent during a probe */ |
||||
av_log(s, AV_LOG_WARNING, "Data type 0x%04x", data_type); |
||||
av_log_missing_feature(s, " in IEC 61937 is", 1); |
||||
} |
||||
return AVERROR_PATCHWELCOME; |
||||
} |
||||
return 0; |
||||
} |
||||
|
||||
/* Largest offset between bursts we currently handle, i.e. AAC with
|
||||
aac_hdr.samples = 4096 */ |
||||
#define SPDIF_MAX_OFFSET 16384 |
||||
|
||||
static int spdif_probe(AVProbeData *p) |
||||
{ |
||||
const uint8_t *buf = p->buf; |
||||
const uint8_t *probe_end = p->buf + FFMIN(2 * SPDIF_MAX_OFFSET, p->buf_size - 1); |
||||
const uint8_t *expected_code = buf + 7; |
||||
uint32_t state = 0; |
||||
int sync_codes = 0; |
||||
int consecutive_codes = 0; |
||||
int offset; |
||||
enum CodecID codec; |
||||
|
||||
for (; buf < probe_end; buf++) { |
||||
state = (state << 8) | *buf; |
||||
|
||||
if (state == (AV_BSWAP16C(SYNCWORD1) << 16 | AV_BSWAP16C(SYNCWORD2)) |
||||
&& buf[1] < 0x37) { |
||||
sync_codes++; |
||||
|
||||
if (buf == expected_code) { |
||||
if (++consecutive_codes >= 2) |
||||
return AVPROBE_SCORE_MAX; |
||||
} else |
||||
consecutive_codes = 0; |
||||
|
||||
if (buf + 4 + AAC_ADTS_HEADER_SIZE > p->buf + p->buf_size) |
||||
break; |
||||
|
||||
/* continue probing to find more sync codes */ |
||||
probe_end = FFMIN(buf + SPDIF_MAX_OFFSET, p->buf + p->buf_size - 1); |
||||
|
||||
/* skip directly to the next sync code */ |
||||
if (!spdif_get_offset_and_codec(NULL, (buf[2] << 8) | buf[1], |
||||
&buf[5], &offset, &codec)) { |
||||
if (buf + offset >= p->buf + p->buf_size) |
||||
break; |
||||
expected_code = buf + offset; |
||||
buf = expected_code - 7; |
||||
} |
||||
} |
||||
} |
||||
|
||||
if (!sync_codes) |
||||
return 0; |
||||
|
||||
if (sync_codes >= 6) |
||||
/* good amount of sync codes but with unexpected offsets */ |
||||
return AVPROBE_SCORE_MAX / 2; |
||||
|
||||
/* some sync codes were found */ |
||||
return AVPROBE_SCORE_MAX / 8; |
||||
} |
||||
|
||||
static int spdif_read_header(AVFormatContext *s, AVFormatParameters *ap) |
||||
{ |
||||
s->ctx_flags |= AVFMTCTX_NOHEADER; |
||||
return 0; |
||||
} |
||||
|
||||
static int spdif_read_packet(AVFormatContext *s, AVPacket *pkt) |
||||
{ |
||||
ByteIOContext *pb = s->pb; |
||||
enum IEC958DataType data_type; |
||||
enum CodecID codec_id; |
||||
uint32_t state = 0; |
||||
int pkt_size_bits, offset, ret; |
||||
|
||||
while (state != (AV_BSWAP16C(SYNCWORD1) << 16 | AV_BSWAP16C(SYNCWORD2))) { |
||||
state = (state << 8) | get_byte(pb); |
||||
if (url_feof(pb)) |
||||
return AVERROR_EOF; |
||||
} |
||||
|
||||
data_type = get_le16(pb); |
||||
pkt_size_bits = get_le16(pb); |
||||
|
||||
if (pkt_size_bits % 16) |
||||
av_log_ask_for_sample(s, "Packet does not end to a 16-bit boundary."); |
||||
|
||||
ret = av_new_packet(pkt, FFALIGN(pkt_size_bits, 16) >> 3); |
||||
if (ret) |
||||
return ret; |
||||
|
||||
pkt->pos = url_ftell(pb) - BURST_HEADER_SIZE; |
||||
|
||||
if (get_buffer(pb, pkt->data, pkt->size) < pkt->size) { |
||||
av_free_packet(pkt); |
||||
return AVERROR_EOF; |
||||
} |
||||
ff_spdif_bswap_buf16((uint16_t *)pkt->data, (uint16_t *)pkt->data, pkt->size >> 1); |
||||
|
||||
ret = spdif_get_offset_and_codec(s, data_type, pkt->data, |
||||
&offset, &codec_id); |
||||
if (ret) { |
||||
av_free_packet(pkt); |
||||
return ret; |
||||
} |
||||
|
||||
/* skip over the padding to the beginning of the next frame */ |
||||
url_fskip(pb, offset - pkt->size - BURST_HEADER_SIZE); |
||||
|
||||
if (!s->nb_streams) { |
||||
/* first packet, create a stream */ |
||||
AVStream *st = av_new_stream(s, 0); |
||||
if (!st) { |
||||
av_free_packet(pkt); |
||||
return AVERROR(ENOMEM); |
||||
} |
||||
st->codec->codec_type = AVMEDIA_TYPE_AUDIO; |
||||
st->codec->codec_id = codec_id; |
||||
} else if (codec_id != s->streams[0]->codec->codec_id) { |
||||
av_log_missing_feature(s, "codec change in IEC 61937", 0); |
||||
return AVERROR_PATCHWELCOME; |
||||
} |
||||
|
||||
if (!s->bit_rate && s->streams[0]->codec->sample_rate) |
||||
/* stream bitrate matches 16-bit stereo PCM bitrate for currently
|
||||
supported codecs */ |
||||
s->bit_rate = 2 * 16 * s->streams[0]->codec->sample_rate; |
||||
|
||||
return 0; |
||||
} |
||||
|
||||
AVInputFormat spdif_demuxer = { |
||||
"spdif", |
||||
NULL_IF_CONFIG_SMALL("IEC 61937 (compressed data in S/PDIF)"), |
||||
0, |
||||
spdif_probe, |
||||
spdif_read_header, |
||||
spdif_read_packet, |
||||
.flags = AVFMT_GENERIC_INDEX, |
||||
}; |
Loading…
Reference in new issue