FFmpeg/libavformat/pmpdec.c
Anton Khirnov 9200514ad8 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.
2016-02-23 17:01:58 +01:00

186 lines
5.5 KiB
C

/*
* PMP demuxer
* Copyright (c) 2011 Reimar Döffinger
*
* 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 "libavutil/intreadwrite.h"
#include "avformat.h"
#include "internal.h"
typedef struct PMPContext {
int cur_stream;
int num_streams;
int audio_packets;
int current_packet;
uint32_t *packet_sizes;
int packet_sizes_alloc;
} PMPContext;
static int pmp_probe(AVProbeData *p)
{
if (!memcmp(p->buf, "pmpm\1\0\0\0", 8))
return AVPROBE_SCORE_MAX;
return 0;
}
static int pmp_header(AVFormatContext *s)
{
PMPContext *pmp = s->priv_data;
AVIOContext *pb = s->pb;
int tb_num, tb_den;
int index_cnt;
int audio_codec_id = AV_CODEC_ID_NONE;
int srate, channels;
int i;
uint64_t pos;
AVStream *vst = avformat_new_stream(s, NULL);
if (!vst)
return AVERROR(ENOMEM);
vst->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
avio_skip(pb, 8);
switch (avio_rl32(pb)) {
case 0:
vst->codecpar->codec_id = AV_CODEC_ID_MPEG4;
break;
case 1:
vst->codecpar->codec_id = AV_CODEC_ID_H264;
break;
default:
av_log(s, AV_LOG_ERROR, "Unsupported video format\n");
break;
}
index_cnt = avio_rl32(pb);
vst->codecpar->width = avio_rl32(pb);
vst->codecpar->height = avio_rl32(pb);
tb_num = avio_rl32(pb);
tb_den = avio_rl32(pb);
avpriv_set_pts_info(vst, 32, tb_num, tb_den);
vst->nb_frames = index_cnt;
vst->duration = index_cnt;
switch (avio_rl32(pb)) {
case 0:
audio_codec_id = AV_CODEC_ID_MP3;
break;
case 1:
av_log(s, AV_LOG_WARNING, "AAC is not yet correctly supported\n");
audio_codec_id = AV_CODEC_ID_AAC;
break;
default:
av_log(s, AV_LOG_ERROR, "Unsupported audio format\n");
break;
}
pmp->num_streams = avio_rl16(pb) + 1;
avio_skip(pb, 10);
srate = avio_rl32(pb);
channels = avio_rl32(pb) + 1;
for (i = 1; i < pmp->num_streams; i++) {
AVStream *ast = avformat_new_stream(s, NULL);
if (!ast)
return AVERROR(ENOMEM);
ast->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
ast->codecpar->codec_id = audio_codec_id;
ast->codecpar->channels = channels;
ast->codecpar->sample_rate = srate;
avpriv_set_pts_info(ast, 32, 1, srate);
}
pos = avio_tell(pb) + 4 * index_cnt;
for (i = 0; i < index_cnt; i++) {
int size = avio_rl32(pb);
int flags = size & 1 ? AVINDEX_KEYFRAME : 0;
size >>= 1;
av_add_index_entry(vst, pos, i, size, 0, flags);
pos += size;
}
return 0;
}
static int pmp_packet(AVFormatContext *s, AVPacket *pkt)
{
PMPContext *pmp = s->priv_data;
AVIOContext *pb = s->pb;
int ret = 0;
int i;
if (pb->eof_reached)
return AVERROR_EOF;
if (pmp->cur_stream == 0) {
int num_packets;
pmp->audio_packets = avio_r8(pb);
if (!pmp->audio_packets) {
av_log(s, AV_LOG_ERROR, "No audio packets.\n");
return AVERROR_INVALIDDATA;
}
num_packets = (pmp->num_streams - 1) * pmp->audio_packets + 1;
avio_skip(pb, 8);
pmp->current_packet = 0;
av_fast_malloc(&pmp->packet_sizes,
&pmp->packet_sizes_alloc,
num_packets * sizeof(*pmp->packet_sizes));
if (!pmp->packet_sizes_alloc) {
av_log(s, AV_LOG_ERROR, "Cannot (re)allocate packet buffer\n");
return AVERROR(ENOMEM);
}
for (i = 0; i < num_packets; i++)
pmp->packet_sizes[i] = avio_rl32(pb);
}
ret = av_get_packet(pb, pkt, pmp->packet_sizes[pmp->current_packet]);
if (ret > 0) {
ret = 0;
// FIXME: this is a hack that should be removed once
// compute_pkt_fields() can handle timestamps properly
if (pmp->cur_stream == 0)
pkt->dts = s->streams[0]->cur_dts++;
pkt->stream_index = pmp->cur_stream;
}
pmp->current_packet++;
if (pmp->current_packet == 1 || pmp->current_packet > pmp->audio_packets)
pmp->cur_stream = (pmp->cur_stream + 1) % pmp->num_streams;
return ret;
}
static int pmp_seek(AVFormatContext *s, int stream_idx, int64_t ts, int flags)
{
PMPContext *pmp = s->priv_data;
pmp->cur_stream = 0;
// fall back on default seek now
return -1;
}
static int pmp_close(AVFormatContext *s)
{
PMPContext *pmp = s->priv_data;
av_freep(&pmp->packet_sizes);
return 0;
}
AVInputFormat ff_pmp_demuxer = {
.name = "pmp",
.long_name = NULL_IF_CONFIG_SMALL("Playstation Portable PMP"),
.priv_data_size = sizeof(PMPContext),
.read_probe = pmp_probe,
.read_header = pmp_header,
.read_packet = pmp_packet,
.read_seek = pmp_seek,
.read_close = pmp_close,
};