FFmpeg: libavformat/iss.c Source File

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libavformat

iss.c

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1 /*

2 * ISS (.iss) file demuxer

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 */

22 /**

23 * @file

24 * Funcom ISS file demuxer

25 * @author Jaikrishnan Menon

26 * @see http://wiki.multimedia.cx/index.php?title=FunCom_ISS

27 */

29 #include "libavutil/channel_layout.h"

30 #include "avformat.h"

31 #include "demux.h"

32 #include "internal.h"

33 #include "libavutil/avstring.h"

35 #define ISS_SIG "IMA_ADPCM_Sound"

36 #define ISS_SIG_LEN 15

37 #define MAX_TOKEN_SIZE 20

39 typedef struct IssDemuxContext {

40 int packet_size;

41 int sample_start_pos;

42 } IssDemuxContext;

44 static void get_token(AVIOContext *s, char *buf, int maxlen)

45 {

46 int i = 0;

47 char c;

49 while ((c = avio_r8(s))) {

50 if(c == ' ')

51 break;

52 if (i < maxlen-1)

53 buf[i++] = c;

54 }

56 if(!c)

57 avio_r8(s);

59 buf[i] = 0; /* Ensure null terminated, but may be truncated */

60 }

62 static int iss_probe(const AVProbeData *p)

63 {

64 if (strncmp(p->buf, ISS_SIG, ISS_SIG_LEN))

65 return 0;

67 return AVPROBE_SCORE_MAX;

68 }

70 static av_cold int iss_read_header(AVFormatContext *s)

71 {

72 IssDemuxContext *iss = s->priv_data;

73 AVIOContext *pb = s->pb;

74 AVStream *st;

75 char token[MAX_TOKEN_SIZE];

76 int stereo, rate_divisor;

78 get_token(pb, token, sizeof(token)); //"IMA_ADPCM_Sound"

79 get_token(pb, token, sizeof(token)); //packet size

80 if (sscanf(token, "%d", &iss->packet_size) != 1) {

81 av_log(s, AV_LOG_ERROR, "Failed parsing packet size\n");

82 return AVERROR_INVALIDDATA;

83 }

84 get_token(pb, token, sizeof(token)); //File ID

85 get_token(pb, token, sizeof(token)); //out size

86 get_token(pb, token, sizeof(token)); //stereo

87 if (sscanf(token, "%d", &stereo) != 1) {

88 av_log(s, AV_LOG_ERROR, "Failed parsing stereo flag\n");

89 return AVERROR_INVALIDDATA;

90 }

91 get_token(pb, token, sizeof(token)); //Unknown1

92 get_token(pb, token, sizeof(token)); //RateDivisor

93 if (sscanf(token, "%d", &rate_divisor) != 1) {

94 av_log(s, AV_LOG_ERROR, "Failed parsing rate_divisor\n");

95 return AVERROR_INVALIDDATA;

96 }

97 get_token(pb, token, sizeof(token)); //Unknown2

98 get_token(pb, token, sizeof(token)); //Version ID

99 get_token(pb, token, sizeof(token)); //Size

100

101 if (iss->packet_size <= 0) {

102 av_log(s, AV_LOG_ERROR, "packet_size %d is invalid\n", iss->packet_size);

103 return AVERROR_INVALIDDATA;

104 }

105

106 iss->sample_start_pos = avio_tell(pb);

107

108 st = avformat_new_stream(s, NULL);

109 if (!st)

110 return AVERROR(ENOMEM);

111 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;

112 st->codecpar->codec_id = AV_CODEC_ID_ADPCM_IMA_ISS;

113

114 if (stereo) {

115 st->codecpar->ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_STEREO;

116 } else {

117 st->codecpar->ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO;

118 }

119

120 st->codecpar->sample_rate = 44100;

121 if(rate_divisor > 0)

122 st->codecpar->sample_rate /= rate_divisor;

123 st->codecpar->bits_per_coded_sample = 4;

124 st->codecpar->bit_rate = st->codecpar->ch_layout.nb_channels *

125 st->codecpar->sample_rate *

126 st->codecpar->bits_per_coded_sample;

127 st->codecpar->block_align = iss->packet_size;

128 avpriv_set_pts_info(st, 32, 1, st->codecpar->sample_rate);

129

130 return 0;

131 }

132

133 static int iss_read_packet(AVFormatContext *s, AVPacket *pkt)

134 {

135 IssDemuxContext *iss = s->priv_data;

136 int ret = av_get_packet(s->pb, pkt, iss->packet_size);

137

138 if(ret != iss->packet_size)

139 return AVERROR(EIO);

140

141 pkt->stream_index = 0;

142 pkt->pts = avio_tell(s->pb) - iss->sample_start_pos;

143 if (s->streams[0]->codecpar->ch_layout.nb_channels > 0)

144 pkt->pts /= s->streams[0]->codecpar->ch_layout.nb_channels * 2;

145 return 0;

146 }

147

148 const FFInputFormat ff_iss_demuxer = {

149 .p.name = "iss",

150 .p.long_name = NULL_IF_CONFIG_SMALL("Funcom ISS"),

151 .priv_data_size = sizeof(IssDemuxContext),

152 .read_probe = iss_probe,

153 .read_header = iss_read_header,

154 .read_packet = iss_read_packet,

155 };

iss_read_packet

static int iss_read_packet(AVFormatContext *s, AVPacket *pkt)

Definition: iss.c:133

AVERROR

Filter the word "frame" indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions

AVCodecParameters::codec_type

enum AVMediaType codec_type

General type of the encoded data.

Definition: codec_par.h:51

AV_CHANNEL_LAYOUT_STEREO

#define AV_CHANNEL_LAYOUT_STEREO

Definition: channel_layout.h:387

avformat_new_stream

AVStream * avformat_new_stream(AVFormatContext *s, const struct AVCodec *c)

Add a new stream to a media file.

AVChannelLayout::nb_channels

int nb_channels

Number of channels in this layout.

Definition: channel_layout.h:321

AVPROBE_SCORE_MAX

#define AVPROBE_SCORE_MAX

maximum score

Definition: avformat.h:463

avpriv_set_pts_info

void avpriv_set_pts_info(AVStream *st, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)

Set the time base and wrapping info for a given stream.

Definition: avformat.c:860

ISS_SIG

#define ISS_SIG

Definition: iss.c:35

avio_tell

static av_always_inline int64_t avio_tell(AVIOContext *s)

ftell() equivalent for AVIOContext.

Definition: avio.h:494

pkt

AVPacket * pkt

Definition: movenc.c:60

AV_LOG_ERROR

#define AV_LOG_ERROR

Something went wrong and cannot losslessly be recovered.

Definition: log.h:180

av_cold

#define av_cold

Definition: attributes.h:90

read_packet

static int read_packet(void *opaque, uint8_t *buf, int buf_size)

Definition: avio_read_callback.c:42

#define s(width, name)

Definition: cbs_vp9.c:198

AVInputFormat::name

const char * name

A comma separated list of short names for the format.

Definition: avformat.h:553

AVProbeData::buf

unsigned char * buf

Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.

Definition: avformat.h:453

AVMEDIA_TYPE_AUDIO

@ AVMEDIA_TYPE_AUDIO

Definition: avutil.h:202

iss_read_header

static av_cold int iss_read_header(AVFormatContext *s)

Definition: iss.c:70

AV_CODEC_ID_ADPCM_IMA_ISS

@ AV_CODEC_ID_ADPCM_IMA_ISS

Definition: codec_id.h:394

IssDemuxContext::packet_size

int packet_size

Definition: iss.c:40

IssDemuxContext::sample_start_pos

int sample_start_pos

Definition: iss.c:41

AVFormatContext

Format I/O context.

Definition: avformat.h:1287

internal.h

AVStream::codecpar

AVCodecParameters * codecpar

Codec parameters associated with this stream.

Definition: avformat.h:771

read_header

static int read_header(FFV1Context *f)

Definition: ffv1dec.c:535

NULL

#define NULL

Definition: coverity.c:32

AVProbeData

This structure contains the data a format has to probe a file.

Definition: avformat.h:451

AVCodecParameters::ch_layout

AVChannelLayout ch_layout

Audio only.

Definition: codec_par.h:180

Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c

Definition: undefined.txt:32

AVCodecParameters::sample_rate

int sample_rate

Audio only.

Definition: codec_par.h:184

AVIOContext

Bytestream IO Context.

Definition: avio.h:160

NULL_IF_CONFIG_SMALL

#define NULL_IF_CONFIG_SMALL(x)

Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.

Definition: internal.h:94