Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

304 lines (270 sloc) 10.709 kb
/*
* id Quake II CIN File Demuxer
* Copyright (c) 2003 The ffmpeg Project
*
* 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
* id Quake II CIN file demuxer by Mike Melanson (melanson@pcisys.net)
* For more information about the id CIN format, visit:
* http://www.csse.monash.edu.au/~timf/
*
* CIN is a somewhat quirky and ill-defined format. Here are some notes
* for anyone trying to understand the technical details of this format:
*
* The format has no definite file signature. This is problematic for a
* general-purpose media player that wants to automatically detect file
* types. However, a CIN file does start with 5 32-bit numbers that
* specify audio and video parameters. This demuxer gets around the lack
* of file signature by performing sanity checks on those parameters.
* Probabalistically, this is a reasonable solution since the number of
* valid combinations of the 5 parameters is a very small subset of the
* total 160-bit number space.
*
* Refer to the function idcin_probe() for the precise A/V parameters
* that this demuxer allows.
*
* Next, each audio and video frame has a duration of 1/14 sec. If the
* audio sample rate is a multiple of the common frequency 22050 Hz it will
* divide evenly by 14. However, if the sample rate is 11025 Hz:
* 11025 (samples/sec) / 14 (frames/sec) = 787.5 (samples/frame)
* The way the CIN stores audio in this case is by storing 787 sample
* frames in the first audio frame and 788 sample frames in the second
* audio frame. Therefore, the total number of bytes in an audio frame
* is given as:
* audio frame #0: 787 * (bytes/sample) * (# channels) bytes in frame
* audio frame #1: 788 * (bytes/sample) * (# channels) bytes in frame
* audio frame #2: 787 * (bytes/sample) * (# channels) bytes in frame
* audio frame #3: 788 * (bytes/sample) * (# channels) bytes in frame
*
* Finally, not all id CIN creation tools agree on the resolution of the
* color palette, apparently. Some creation tools specify red, green, and
* blue palette components in terms of 6-bit VGA color DAC values which
* range from 0..63. Other tools specify the RGB components as full 8-bit
* values that range from 0..255. Since there are no markers in the file to
* differentiate between the two variants, this demuxer uses the following
* heuristic:
* - load the 768 palette bytes from disk
* - assume that they will need to be shifted left by 2 bits to
* transform them from 6-bit values to 8-bit values
* - scan through all 768 palette bytes
* - if any bytes exceed 63, do not shift the bytes at all before
* transmitting them to the video decoder
*/
#include "libavutil/intreadwrite.h"
#include "avformat.h"
#include "internal.h"
#define HUFFMAN_TABLE_SIZE (64 * 1024)
#define IDCIN_FPS 14
typedef struct IdcinDemuxContext {
int video_stream_index;
int audio_stream_index;
int audio_chunk_size1;
int audio_chunk_size2;
/* demux state variables */
int current_audio_chunk;
int next_chunk_is_video;
int audio_present;
int64_t pts;
} IdcinDemuxContext;
static int idcin_probe(AVProbeData *p)
{
unsigned int number;
/*
* This is what you could call a "probabilistic" file check: id CIN
* files don't have a definite file signature. In lieu of such a marker,
* perform sanity checks on the 5 32-bit header fields:
* width, height: greater than 0, less than or equal to 1024
* audio sample rate: greater than or equal to 8000, less than or
* equal to 48000, or 0 for no audio
* audio sample width (bytes/sample): 0 for no audio, or 1 or 2
* audio channels: 0 for no audio, or 1 or 2
*/
/* check we have enough data to do all checks, otherwise the
0-padding may cause a wrong recognition */
if (p->buf_size < 20)
return 0;
/* check the video width */
number = AV_RL32(&p->buf[0]);
if ((number == 0) || (number > 1024))
return 0;
/* check the video height */
number = AV_RL32(&p->buf[4]);
if ((number == 0) || (number > 1024))
return 0;
/* check the audio sample rate */
number = AV_RL32(&p->buf[8]);
if ((number != 0) && ((number < 8000) | (number > 48000)))
return 0;
/* check the audio bytes/sample */
number = AV_RL32(&p->buf[12]);
if (number > 2)
return 0;
/* check the audio channels */
number = AV_RL32(&p->buf[16]);
if (number > 2)
return 0;
/* return half certainly since this check is a bit sketchy */
return AVPROBE_SCORE_MAX / 2;
}
static int idcin_read_header(AVFormatContext *s)
{
AVIOContext *pb = s->pb;
IdcinDemuxContext *idcin = s->priv_data;
AVStream *st;
unsigned int width, height;
unsigned int sample_rate, bytes_per_sample, channels;
/* get the 5 header parameters */
width = avio_rl32(pb);
height = avio_rl32(pb);
sample_rate = avio_rl32(pb);
bytes_per_sample = avio_rl32(pb);
channels = avio_rl32(pb);
st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
avpriv_set_pts_info(st, 33, 1, IDCIN_FPS);
idcin->video_stream_index = st->index;
st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
st->codec->codec_id = AV_CODEC_ID_IDCIN;
st->codec->codec_tag = 0; /* no fourcc */
st->codec->width = width;
st->codec->height = height;
/* load up the Huffman tables into extradata */
st->codec->extradata_size = HUFFMAN_TABLE_SIZE;
st->codec->extradata = av_malloc(HUFFMAN_TABLE_SIZE);
if (avio_read(pb, st->codec->extradata, HUFFMAN_TABLE_SIZE) !=
HUFFMAN_TABLE_SIZE)
return AVERROR(EIO);
/* if sample rate is 0, assume no audio */
if (sample_rate) {
idcin->audio_present = 1;
st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
avpriv_set_pts_info(st, 33, 1, IDCIN_FPS);
idcin->audio_stream_index = st->index;
st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
st->codec->codec_tag = 1;
st->codec->channels = channels;
st->codec->sample_rate = sample_rate;
st->codec->bits_per_coded_sample = bytes_per_sample * 8;
st->codec->bit_rate = sample_rate * bytes_per_sample * 8 * channels;
st->codec->block_align = bytes_per_sample * channels;
if (bytes_per_sample == 1)
st->codec->codec_id = AV_CODEC_ID_PCM_U8;
else
st->codec->codec_id = AV_CODEC_ID_PCM_S16LE;
if (sample_rate % 14 != 0) {
idcin->audio_chunk_size1 = (sample_rate / 14) *
bytes_per_sample * channels;
idcin->audio_chunk_size2 = (sample_rate / 14 + 1) *
bytes_per_sample * channels;
} else {
idcin->audio_chunk_size1 = idcin->audio_chunk_size2 =
(sample_rate / 14) * bytes_per_sample * channels;
}
idcin->current_audio_chunk = 0;
} else
idcin->audio_present = 1;
idcin->next_chunk_is_video = 1;
idcin->pts = 0;
return 0;
}
static int idcin_read_packet(AVFormatContext *s,
AVPacket *pkt)
{
int ret;
unsigned int command;
unsigned int chunk_size;
IdcinDemuxContext *idcin = s->priv_data;
AVIOContext *pb = s->pb;
int i;
int palette_scale;
unsigned char r, g, b;
unsigned char palette_buffer[768];
uint32_t palette[256];
if (url_feof(s->pb))
return AVERROR(EIO);
if (idcin->next_chunk_is_video) {
command = avio_rl32(pb);
if (command == 2) {
return AVERROR(EIO);
} else if (command == 1) {
/* trigger a palette change */
if (avio_read(pb, palette_buffer, 768) != 768)
return AVERROR(EIO);
/* scale the palette as necessary */
palette_scale = 2;
for (i = 0; i < 768; i++)
if (palette_buffer[i] > 63) {
palette_scale = 0;
break;
}
for (i = 0; i < 256; i++) {
r = palette_buffer[i * 3 ] << palette_scale;
g = palette_buffer[i * 3 + 1] << palette_scale;
b = palette_buffer[i * 3 + 2] << palette_scale;
palette[i] = (0xFFU << 24) | (r << 16) | (g << 8) | (b);
if (palette_scale == 2)
palette[i] |= palette[i] >> 6 & 0x30303;
}
}
chunk_size = avio_rl32(pb);
/* skip the number of decoded bytes (always equal to width * height) */
avio_skip(pb, 4);
chunk_size -= 4;
ret= av_get_packet(pb, pkt, chunk_size);
if (ret < 0)
return ret;
if (command == 1) {
uint8_t *pal;
pal = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE,
AVPALETTE_SIZE);
if (!pal)
return AVERROR(ENOMEM);
memcpy(pal, palette, AVPALETTE_SIZE);
}
pkt->stream_index = idcin->video_stream_index;
pkt->pts = idcin->pts;
} else {
/* send out the audio chunk */
if (idcin->current_audio_chunk)
chunk_size = idcin->audio_chunk_size2;
else
chunk_size = idcin->audio_chunk_size1;
ret= av_get_packet(pb, pkt, chunk_size);
if (ret < 0)
return ret;
pkt->stream_index = idcin->audio_stream_index;
pkt->pts = idcin->pts;
idcin->current_audio_chunk ^= 1;
idcin->pts++;
}
if (idcin->audio_present)
idcin->next_chunk_is_video ^= 1;
return ret;
}
AVInputFormat ff_idcin_demuxer = {
.name = "idcin",
.long_name = NULL_IF_CONFIG_SMALL("id Cinematic"),
.priv_data_size = sizeof(IdcinDemuxContext),
.read_probe = idcin_probe,
.read_header = idcin_read_header,
.read_packet = idcin_read_packet,
};
Jump to Line
Something went wrong with that request. Please try again.