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ffmpeg/libavformat/rl2.c

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/*
* RL2 Format Demuxer
* Copyright (c) 2008 Sascha Sommer (saschasommer@freenet.de)
*
* 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
*/
/**
* RL2 file demuxer
* @file
* @author Sascha Sommer (saschasommer@freenet.de)
* For more information regarding the RL2 file format, visit:
* http://wiki.multimedia.cx/index.php?title=RL2
*
* extradata:
* 2 byte le initial drawing offset within 320x200 viewport
* 4 byte le number of used colors
* 256 * 3 bytes rgb palette
* optional background_frame
*/
#include "libavutil/intreadwrite.h"
#include "avformat.h"
#define EXTRADATA1_SIZE (6 + 256 * 3) ///< video base, clr, palette
#define FORM_TAG MKBETAG('F', 'O', 'R', 'M')
#define RLV2_TAG MKBETAG('R', 'L', 'V', '2')
#define RLV3_TAG MKBETAG('R', 'L', 'V', '3')
typedef struct Rl2DemuxContext {
unsigned int index_pos[2]; ///< indexes in the sample tables
} Rl2DemuxContext;
/**
* check if the file is in rl2 format
* @param p probe buffer
* @return 0 when the probe buffer does not contain rl2 data, > 0 otherwise
*/
static int rl2_probe(AVProbeData *p)
{
if(AV_RB32(&p->buf[0]) != FORM_TAG)
return 0;
if(AV_RB32(&p->buf[8]) != RLV2_TAG &&
AV_RB32(&p->buf[8]) != RLV3_TAG)
return 0;
return AVPROBE_SCORE_MAX;
}
/**
* read rl2 header data and setup the avstreams
* @param s demuxer context
* @param ap format parameters
* @return 0 on success, AVERROR otherwise
*/
static av_cold int rl2_read_header(AVFormatContext *s,
AVFormatParameters *ap)
{
AVIOContext *pb = s->pb;
AVStream *st;
unsigned int frame_count;
unsigned int audio_frame_counter = 0;
unsigned int video_frame_counter = 0;
unsigned int back_size;
int data_size;
unsigned short encoding_method;
unsigned short sound_rate;
unsigned short rate;
unsigned short channels;
unsigned short def_sound_size;
unsigned int signature;
unsigned int pts_den = 11025; /* video only case */
unsigned int pts_num = 1103;
unsigned int* chunk_offset = NULL;
int* chunk_size = NULL;
int* audio_size = NULL;
int i;
int ret = 0;
avio_skip(pb,4); /* skip FORM tag */
back_size = avio_rl32(pb); /**< get size of the background frame */
signature = avio_rb32(pb);
data_size = avio_rb32(pb);
frame_count = avio_rl32(pb);
/* disallow back_sizes and frame_counts that may lead to overflows later */
if(back_size > INT_MAX/2 || frame_count > INT_MAX / sizeof(uint32_t))
return AVERROR_INVALIDDATA;
encoding_method = avio_rl16(pb);
sound_rate = avio_rl16(pb);
rate = avio_rl16(pb);
channels = avio_rl16(pb);
def_sound_size = avio_rl16(pb);
/** setup video stream */
st = av_new_stream(s, 0);
if(!st)
return AVERROR(ENOMEM);
st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
st->codec->codec_id = CODEC_ID_RL2;
st->codec->codec_tag = 0; /* no fourcc */
st->codec->width = 320;
st->codec->height = 200;
/** allocate and fill extradata */
st->codec->extradata_size = EXTRADATA1_SIZE;
if(signature == RLV3_TAG && back_size > 0)
st->codec->extradata_size += back_size;
st->codec->extradata = av_mallocz(st->codec->extradata_size +
FF_INPUT_BUFFER_PADDING_SIZE);
if(!st->codec->extradata)
return AVERROR(ENOMEM);
if(avio_read(pb,st->codec->extradata,st->codec->extradata_size) !=
st->codec->extradata_size)
return AVERROR(EIO);
/** setup audio stream if present */
if(sound_rate){
pts_num = def_sound_size;
pts_den = rate;
st = av_new_stream(s, 0);
if (!st)
return AVERROR(ENOMEM);
st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
st->codec->codec_id = CODEC_ID_PCM_U8;
st->codec->codec_tag = 1;
st->codec->channels = channels;
st->codec->bits_per_coded_sample = 8;
st->codec->sample_rate = rate;
st->codec->bit_rate = st->codec->channels * st->codec->sample_rate *
st->codec->bits_per_coded_sample;
st->codec->block_align = st->codec->channels *
st->codec->bits_per_coded_sample / 8;
av_set_pts_info(st,32,1,rate);
}
av_set_pts_info(s->streams[0], 32, pts_num, pts_den);
chunk_size = av_malloc(frame_count * sizeof(uint32_t));
audio_size = av_malloc(frame_count * sizeof(uint32_t));
chunk_offset = av_malloc(frame_count * sizeof(uint32_t));
if(!chunk_size || !audio_size || !chunk_offset){
av_free(chunk_size);
av_free(audio_size);
av_free(chunk_offset);
return AVERROR(ENOMEM);
}
/** read offset and size tables */
for(i=0; i < frame_count;i++)
chunk_size[i] = avio_rl32(pb);
for(i=0; i < frame_count;i++)
chunk_offset[i] = avio_rl32(pb);
for(i=0; i < frame_count;i++)
audio_size[i] = avio_rl32(pb) & 0xFFFF;
/** build the sample index */
for(i=0;i<frame_count;i++){
if(chunk_size[i] < 0 || audio_size[i] > chunk_size[i]){
ret = AVERROR_INVALIDDATA;
break;
}
if(sound_rate && audio_size[i]){
av_add_index_entry(s->streams[1], chunk_offset[i],
audio_frame_counter,audio_size[i], 0, AVINDEX_KEYFRAME);
audio_frame_counter += audio_size[i] / channels;
}
av_add_index_entry(s->streams[0], chunk_offset[i] + audio_size[i],
video_frame_counter,chunk_size[i]-audio_size[i],0,AVINDEX_KEYFRAME);
++video_frame_counter;
}
av_free(chunk_size);
av_free(audio_size);
av_free(chunk_offset);
return ret;
}
/**
* read a single audio or video packet
* @param s demuxer context
* @param pkt the packet to be filled
* @return 0 on success, AVERROR otherwise
*/
static int rl2_read_packet(AVFormatContext *s,
AVPacket *pkt)
{
Rl2DemuxContext *rl2 = s->priv_data;
AVIOContext *pb = s->pb;
AVIndexEntry *sample = NULL;
int i;
int ret = 0;
int stream_id = -1;
int64_t pos = INT64_MAX;
/** check if there is a valid video or audio entry that can be used */
for(i=0; i<s->nb_streams; i++){
if(rl2->index_pos[i] < s->streams[i]->nb_index_entries
&& s->streams[i]->index_entries[ rl2->index_pos[i] ].pos < pos){
sample = &s->streams[i]->index_entries[ rl2->index_pos[i] ];
pos= sample->pos;
stream_id= i;
}
}
if(stream_id == -1)
return AVERROR(EIO);
++rl2->index_pos[stream_id];
/** position the stream (will probably be there anyway) */
avio_seek(pb, sample->pos, SEEK_SET);
/** fill the packet */
ret = av_get_packet(pb, pkt, sample->size);
if(ret != sample->size){
av_free_packet(pkt);
return AVERROR(EIO);
}
pkt->stream_index = stream_id;
pkt->pts = sample->timestamp;
return ret;
}
/**
* seek to a new timestamp
* @param s demuxer context
* @param stream_index index of the stream that should be seeked
* @param timestamp wanted timestamp
* @param flags direction and seeking mode
* @return 0 on success, -1 otherwise
*/
static int rl2_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
{
AVStream *st = s->streams[stream_index];
Rl2DemuxContext *rl2 = s->priv_data;
int i;
int index = av_index_search_timestamp(st, timestamp, flags);
if(index < 0)
return -1;
rl2->index_pos[stream_index] = index;
timestamp = st->index_entries[index].timestamp;
for(i=0; i < s->nb_streams; i++){
AVStream *st2 = s->streams[i];
index = av_index_search_timestamp(st2,
av_rescale_q(timestamp, st->time_base, st2->time_base),
flags | AVSEEK_FLAG_BACKWARD);
if(index < 0)
index = 0;
rl2->index_pos[i] = index;
}
return 0;
}
AVInputFormat ff_rl2_demuxer = {
"rl2",
NULL_IF_CONFIG_SMALL("RL2 format"),
sizeof(Rl2DemuxContext),
rl2_probe,
rl2_read_header,
rl2_read_packet,
NULL,
rl2_read_seek,
};
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