ffmpeg/libavformat/rl2.c

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/*
* RL2 Format Demuxer
* Copyright (c) 2008 Sascha Sommer (saschasommer@freenet.de)
*
* 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
*/
/**
* RL2 file demuxer
* @file
* @author Sascha Sommer (saschasommer@freenet.de)
* @see 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 <stdint.h>
#include "libavutil/intreadwrite.h"
#include "libavutil/mathematics.h"
#include "avformat.h"
#include "internal.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
* @return 0 on success, AVERROR otherwise
*/
static av_cold int rl2_read_header(AVFormatContext *s)
{
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;
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);
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avio_skip(pb, 4); /* data size */
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;
avio_skip(pb, 2); /* encoding method */
sound_rate = avio_rl16(pb);
rate = avio_rl16(pb);
channels = avio_rl16(pb);
def_sound_size = avio_rl16(pb);
/** setup video stream */
st = avformat_new_stream(s, NULL);
if(!st)
return AVERROR(ENOMEM);
lavf: replace AVStream.codec with AVStream.codecpar Currently, AVStream contains an embedded AVCodecContext instance, which is used by demuxers to export stream parameters to the caller and by muxers to receive stream parameters from the caller. It is also used internally as the codec context that is passed to parsers. In addition, it is also widely used by the callers as the decoding (when demuxer) or encoding (when muxing) context, though this has been officially discouraged since Libav 11. There are multiple important problems with this approach: - the fields in AVCodecContext are in general one of * stream parameters * codec options * codec state However, it's not clear which ones are which. It is consequently unclear which fields are a demuxer allowed to set or a muxer allowed to read. This leads to erratic behaviour depending on whether decoding or encoding is being performed or not (and whether it uses the AVStream embedded codec context). - various synchronization issues arising from the fact that the same context is used by several different APIs (muxers/demuxers, parsers, bitstream filters and encoders/decoders) simultaneously, with there being no clear rules for who can modify what and the different processes being typically delayed with respect to each other. - avformat_find_stream_info() making it necessary to support opening and closing a single codec context multiple times, thus complicating the semantics of freeing various allocated objects in the codec context. Those problems are resolved by replacing the AVStream embedded codec context with a newly added AVCodecParameters instance, which stores only the stream parameters exported by the demuxers or read by the muxers.
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st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
st->codecpar->codec_id = AV_CODEC_ID_RL2;
st->codecpar->codec_tag = 0; /* no fourcc */
st->codecpar->width = 320;
st->codecpar->height = 200;
/** allocate and fill extradata */
lavf: replace AVStream.codec with AVStream.codecpar Currently, AVStream contains an embedded AVCodecContext instance, which is used by demuxers to export stream parameters to the caller and by muxers to receive stream parameters from the caller. It is also used internally as the codec context that is passed to parsers. In addition, it is also widely used by the callers as the decoding (when demuxer) or encoding (when muxing) context, though this has been officially discouraged since Libav 11. There are multiple important problems with this approach: - the fields in AVCodecContext are in general one of * stream parameters * codec options * codec state However, it's not clear which ones are which. It is consequently unclear which fields are a demuxer allowed to set or a muxer allowed to read. This leads to erratic behaviour depending on whether decoding or encoding is being performed or not (and whether it uses the AVStream embedded codec context). - various synchronization issues arising from the fact that the same context is used by several different APIs (muxers/demuxers, parsers, bitstream filters and encoders/decoders) simultaneously, with there being no clear rules for who can modify what and the different processes being typically delayed with respect to each other. - avformat_find_stream_info() making it necessary to support opening and closing a single codec context multiple times, thus complicating the semantics of freeing various allocated objects in the codec context. Those problems are resolved by replacing the AVStream embedded codec context with a newly added AVCodecParameters instance, which stores only the stream parameters exported by the demuxers or read by the muxers.
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st->codecpar->extradata_size = EXTRADATA1_SIZE;
if(signature == RLV3_TAG && back_size > 0)
lavf: replace AVStream.codec with AVStream.codecpar Currently, AVStream contains an embedded AVCodecContext instance, which is used by demuxers to export stream parameters to the caller and by muxers to receive stream parameters from the caller. It is also used internally as the codec context that is passed to parsers. In addition, it is also widely used by the callers as the decoding (when demuxer) or encoding (when muxing) context, though this has been officially discouraged since Libav 11. There are multiple important problems with this approach: - the fields in AVCodecContext are in general one of * stream parameters * codec options * codec state However, it's not clear which ones are which. It is consequently unclear which fields are a demuxer allowed to set or a muxer allowed to read. This leads to erratic behaviour depending on whether decoding or encoding is being performed or not (and whether it uses the AVStream embedded codec context). - various synchronization issues arising from the fact that the same context is used by several different APIs (muxers/demuxers, parsers, bitstream filters and encoders/decoders) simultaneously, with there being no clear rules for who can modify what and the different processes being typically delayed with respect to each other. - avformat_find_stream_info() making it necessary to support opening and closing a single codec context multiple times, thus complicating the semantics of freeing various allocated objects in the codec context. Those problems are resolved by replacing the AVStream embedded codec context with a newly added AVCodecParameters instance, which stores only the stream parameters exported by the demuxers or read by the muxers.
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st->codecpar->extradata_size += back_size;
if(ff_get_extradata(s, st->codecpar, pb, st->codecpar->extradata_size) < 0)
return AVERROR(ENOMEM);
/** setup audio stream if present */
if(sound_rate){
if (!channels || channels > 42) {
av_log(s, AV_LOG_ERROR, "Invalid number of channels: %d\n", channels);
return AVERROR_INVALIDDATA;
}
pts_num = def_sound_size;
pts_den = rate;
st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
lavf: replace AVStream.codec with AVStream.codecpar Currently, AVStream contains an embedded AVCodecContext instance, which is used by demuxers to export stream parameters to the caller and by muxers to receive stream parameters from the caller. It is also used internally as the codec context that is passed to parsers. In addition, it is also widely used by the callers as the decoding (when demuxer) or encoding (when muxing) context, though this has been officially discouraged since Libav 11. There are multiple important problems with this approach: - the fields in AVCodecContext are in general one of * stream parameters * codec options * codec state However, it's not clear which ones are which. It is consequently unclear which fields are a demuxer allowed to set or a muxer allowed to read. This leads to erratic behaviour depending on whether decoding or encoding is being performed or not (and whether it uses the AVStream embedded codec context). - various synchronization issues arising from the fact that the same context is used by several different APIs (muxers/demuxers, parsers, bitstream filters and encoders/decoders) simultaneously, with there being no clear rules for who can modify what and the different processes being typically delayed with respect to each other. - avformat_find_stream_info() making it necessary to support opening and closing a single codec context multiple times, thus complicating the semantics of freeing various allocated objects in the codec context. Those problems are resolved by replacing the AVStream embedded codec context with a newly added AVCodecParameters instance, which stores only the stream parameters exported by the demuxers or read by the muxers.
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st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
st->codecpar->codec_id = AV_CODEC_ID_PCM_U8;
st->codecpar->codec_tag = 1;
st->codecpar->channels = channels;
st->codecpar->bits_per_coded_sample = 8;
st->codecpar->sample_rate = rate;
st->codecpar->bit_rate = st->codecpar->channels * st->codecpar->sample_rate *
st->codecpar->bits_per_coded_sample;
st->codecpar->block_align = st->codecpar->channels *
st->codecpar->bits_per_coded_sample / 8;
avpriv_set_pts_info(st,32,1,rate);
}
avpriv_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_EOF;
++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_packet_unref(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 = {
.name = "rl2",
.long_name = NULL_IF_CONFIG_SMALL("RL2"),
.priv_data_size = sizeof(Rl2DemuxContext),
.read_probe = rl2_probe,
.read_header = rl2_read_header,
.read_packet = rl2_read_packet,
.read_seek = rl2_read_seek,
};