ffmpeg/libavformat/hnm.c

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/*
* Cryo Interactive Entertainment HNM4 demuxer
*
* Copyright (c) 2012 David Kment
*
* 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
*/
#include <inttypes.h>
#include "libavutil/intreadwrite.h"
#include "avformat.h"
#include "internal.h"
#define HNM4_TAG MKTAG('H', 'N', 'M', '4')
#define HNM4_SAMPLE_RATE 22050
#define HNM4_FRAME_FPS 24
#define HNM4_CHUNK_ID_PL 19536
#define HNM4_CHUNK_ID_IZ 23113
#define HNM4_CHUNK_ID_IU 21833
#define HNM4_CHUNK_ID_SD 17491
typedef struct Hnm4DemuxContext {
uint8_t version;
uint16_t width;
uint16_t height;
uint32_t filesize;
uint32_t frames;
uint32_t taboffset;
uint16_t bits;
uint16_t channels;
uint32_t framesize;
uint32_t currentframe;
int64_t pts;
uint32_t superchunk_remaining;
AVPacket vpkt;
} Hnm4DemuxContext;
static int hnm_probe(AVProbeData *p)
{
if (p->buf_size < 4)
return 0;
// check for HNM4 header.
// currently only HNM v4/v4A is supported
if (AV_RL32(&p->buf[0]) == HNM4_TAG)
return AVPROBE_SCORE_MAX;
return 0;
}
static int hnm_read_header(AVFormatContext *s)
{
Hnm4DemuxContext *hnm = s->priv_data;
AVIOContext *pb = s->pb;
AVStream *vst;
/* default context members */
hnm->pts = 0;
av_init_packet(&hnm->vpkt);
hnm->vpkt.data = NULL;
hnm->vpkt.size = 0;
hnm->superchunk_remaining = 0;
avio_skip(pb, 8);
hnm->width = avio_rl16(pb);
hnm->height = avio_rl16(pb);
hnm->filesize = avio_rl32(pb);
hnm->frames = avio_rl32(pb);
hnm->taboffset = avio_rl32(pb);
hnm->bits = avio_rl16(pb);
hnm->channels = avio_rl16(pb);
hnm->framesize = avio_rl32(pb);
avio_skip(pb, 32);
hnm->currentframe = 0;
if (hnm->width < 320 || hnm->width > 640 ||
hnm->height < 150 || hnm->height > 480) {
av_log(s, AV_LOG_ERROR,
"invalid resolution: %ux%u\n", hnm->width, hnm->height);
return AVERROR_INVALIDDATA;
}
// TODO: find a better way to detect HNM4A
if (hnm->width == 640)
hnm->version = 0x4a;
else
hnm->version = 0x40;
if (!(vst = avformat_new_stream(s, NULL)))
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.
2014-06-18 18:42:52 +00:00
vst->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
vst->codecpar->codec_id = AV_CODEC_ID_HNM4_VIDEO;
vst->codecpar->codec_tag = 0;
vst->codecpar->width = hnm->width;
vst->codecpar->height = hnm->height;
vst->codecpar->extradata = av_mallocz(1);
vst->codecpar->extradata_size = 1;
memcpy(vst->codecpar->extradata, &hnm->version, 1);
vst->start_time = 0;
avpriv_set_pts_info(vst, 33, 1, HNM4_FRAME_FPS);
return 0;
}
static int hnm_read_packet(AVFormatContext *s, AVPacket *pkt)
{
Hnm4DemuxContext *hnm = s->priv_data;
AVIOContext *pb = s->pb;
int ret = 0;
uint32_t superchunk_size, chunk_size;
uint16_t chunk_id;
if (hnm->currentframe == hnm->frames || pb->eof_reached)
return AVERROR_EOF;
if (hnm->superchunk_remaining == 0) {
/* parse next superchunk */
superchunk_size = avio_rl24(pb);
avio_skip(pb, 1);
hnm->superchunk_remaining = superchunk_size - 4;
}
chunk_size = avio_rl24(pb);
avio_skip(pb, 1);
chunk_id = avio_rl16(pb);
avio_skip(pb, 2);
if (chunk_size > hnm->superchunk_remaining) {
av_log(s, AV_LOG_ERROR,
"invalid chunk size: %"PRIu32", offset: %"PRId64"\n",
chunk_size, avio_tell(pb));
avio_skip(pb, hnm->superchunk_remaining - 8);
hnm->superchunk_remaining = 0;
}
switch (chunk_id) {
case HNM4_CHUNK_ID_PL:
case HNM4_CHUNK_ID_IZ:
case HNM4_CHUNK_ID_IU:
avio_seek(pb, -8, SEEK_CUR);
ret += av_get_packet(pb, pkt, chunk_size);
hnm->superchunk_remaining -= chunk_size;
if (chunk_id == HNM4_CHUNK_ID_IZ || chunk_id == HNM4_CHUNK_ID_IU)
hnm->currentframe++;
break;
case HNM4_CHUNK_ID_SD:
avio_skip(pb, chunk_size - 8);
hnm->superchunk_remaining -= chunk_size;
break;
default:
av_log(s, AV_LOG_WARNING, "unknown chunk found: %"PRIu16", offset: %"PRId64"\n",
chunk_id, avio_tell(pb));
avio_skip(pb, chunk_size - 8);
hnm->superchunk_remaining -= chunk_size;
break;
}
return ret;
}
static int hnm_read_close(AVFormatContext *s)
{
Hnm4DemuxContext *hnm = s->priv_data;
if (hnm->vpkt.size > 0)
av_packet_unref(&hnm->vpkt);
return 0;
}
AVInputFormat ff_hnm_demuxer = {
.name = "hnm",
.long_name = NULL_IF_CONFIG_SMALL("Cryo HNM v4"),
.priv_data_size = sizeof(Hnm4DemuxContext),
.read_probe = hnm_probe,
.read_header = hnm_read_header,
.read_packet = hnm_read_packet,
.read_close = hnm_read_close,
.flags = AVFMT_NO_BYTE_SEEK | AVFMT_NOGENSEARCH | AVFMT_NOBINSEARCH
};