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ffmpeg/libavformat/moflex.c

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/*
* MOFLEX demuxer
* Copyright (c) 2020 Paul B Mahol
*
* 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
*/
#include "libavcodec/bytestream.h"
#include "avformat.h"
#include "internal.h"
typedef struct BitReader {
unsigned last;
unsigned pos;
} BitReader;
typedef struct MOFLEXDemuxContext {
unsigned size;
int64_t pos;
int64_t ts;
int flags;
int in_block;
BitReader br;
} MOFLEXDemuxContext;
static int pop(BitReader *br, AVIOContext *pb)
{
if (avio_feof(pb))
return AVERROR_EOF;
if ((br->pos & 7) == 0)
br->last = (unsigned)avio_r8(pb) << 24U;
else
br->last <<= 1;
br->pos++;
return !!(br->last & 0x80000000);
}
static int pop_int(BitReader *br, AVIOContext *pb, int n)
{
int value = 0;
for (int i = 0; i < n; i++) {
int ret = pop(br, pb);
if (ret < 0)
return ret;
if (ret > INT_MAX - value - value)
return AVERROR_INVALIDDATA;
value = 2 * value + ret;
}
return value;
}
static int pop_length(BitReader *br, AVIOContext *pb)
{
int ret, n = 1;
while ((ret = pop(br, pb)) == 0)
n++;
if (ret < 0)
return ret;
return n;
}
static int read_var_byte(AVFormatContext *s, unsigned *out)
{
AVIOContext *pb = s->pb;
unsigned value = 0, data;
data = avio_r8(pb);
if (!(data & 0x80)) {
*out = data;
return 0;
}
value = (data & 0x7F) << 7;
data = avio_r8(pb);
if (!(data & 0x80)) {
value |= data;
*out = value;
return 0;
}
value = ((data & 0x7F) | value) << 7;
data = avio_r8(pb);
if (!(data & 0x80)) {
value |= data;
*out = value;
return 0;
}
value = (((data & 0x7F) | value) << 7) | avio_r8(pb);
*out = value;
return 0;
}
static int moflex_probe(const AVProbeData *p)
{
GetByteContext gb;
int score = 0;
bytestream2_init(&gb, p->buf, p->buf_size);
if (bytestream2_get_be16(&gb) != 0x4C32)
return 0;
score += 10;
bytestream2_skip(&gb, 10);
if (bytestream2_get_be16(&gb) == 0)
return 0;
score += 5;
while (bytestream2_get_bytes_left(&gb) > 0) {
int type = bytestream2_get_byte(&gb);
int size = bytestream2_get_byte(&gb);
if (type == 0) {
score += 5 * (size == 0);
break;
}
if ((type == 1 && size == 12) ||
(type == 2 && size == 6) ||
(type == 3 && size == 13) ||
(type == 4 && size == 2))
score += 20;
bytestream2_skip(&gb, size);
}
return FFMIN(AVPROBE_SCORE_MAX, score);
}
static int moflex_read_sync(AVFormatContext *s)
{
MOFLEXDemuxContext *m = s->priv_data;
AVIOContext *pb = s->pb;
if (avio_rb16(pb) != 0x4C32) {
if (avio_feof(pb))
return AVERROR_EOF;
avio_seek(pb, -2, SEEK_CUR);
return 1;
}
avio_skip(pb, 2);
m->ts = avio_rb64(pb);
m->size = avio_rb16(pb) + 1;
while (!avio_feof(pb)) {
unsigned type, ssize, codec_id = 0;
unsigned codec_type, width = 0, height = 0, sample_rate = 0, channels = 0;
int stream_index = -1;
int format;
AVRational fps;
read_var_byte(s, &type);
read_var_byte(s, &ssize);
switch (type) {
case 0:
if (ssize > 0)
avio_skip(pb, ssize);
return 0;
case 2:
codec_type = AVMEDIA_TYPE_AUDIO;
stream_index = avio_r8(pb);
codec_id = avio_r8(pb);
switch (codec_id) {
case 0: codec_id = AV_CODEC_ID_FASTAUDIO; break;
case 1: codec_id = AV_CODEC_ID_ADPCM_IMA_MOFLEX; break;
case 2: codec_id = AV_CODEC_ID_PCM_S16LE; break;
default:
av_log(s, AV_LOG_ERROR, "Unsupported audio codec: %d\n", codec_id);
return AVERROR_PATCHWELCOME;
}
sample_rate = avio_rb24(pb) + 1;
channels = avio_r8(pb) + 1;
break;
case 1:
case 3:
codec_type = AVMEDIA_TYPE_VIDEO;
stream_index = avio_r8(pb);
codec_id = avio_r8(pb);
switch (codec_id) {
case 0: codec_id = AV_CODEC_ID_MOBICLIP; break;
default:
av_log(s, AV_LOG_ERROR, "Unsupported video codec: %d\n", codec_id);
return AVERROR_PATCHWELCOME;
}
fps.num = avio_rb16(pb);
fps.den = avio_rb16(pb);
width = avio_rb16(pb);
height = avio_rb16(pb);
format = AV_PIX_FMT_YUV420P;
avio_skip(pb, type == 3 ? 3 : 2);
break;
case 4:
codec_type = AVMEDIA_TYPE_DATA;
stream_index = avio_r8(pb);
avio_skip(pb, 1);
break;
}
if (stream_index == s->nb_streams) {
AVStream *st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
st->codecpar->codec_type = codec_type;
st->codecpar->codec_id = codec_id;
st->codecpar->width = width;
st->codecpar->height = height;
st->codecpar->sample_rate= sample_rate;
st->codecpar->channels = channels;
st->codecpar->format = format;
st->priv_data = av_packet_alloc();
if (!st->priv_data)
return AVERROR(ENOMEM);
if (sample_rate)
avpriv_set_pts_info(st, 63, 1, sample_rate);
else
avpriv_set_pts_info(st, 63, fps.den, fps.num);
}
}
return 0;
}
static int moflex_read_header(AVFormatContext *s)
{
int ret;
ret = moflex_read_sync(s);
if (ret < 0)
return ret;
s->ctx_flags |= AVFMTCTX_NOHEADER;
avio_seek(s->pb, 0, SEEK_SET);
return 0;
}
static int moflex_read_packet(AVFormatContext *s, AVPacket *pkt)
{
MOFLEXDemuxContext *m = s->priv_data;
AVIOContext *pb = s->pb;
BitReader *br = &m->br;
int ret;
while (!avio_feof(pb)) {
if (!m->in_block) {
m->pos = avio_tell(pb);
ret = moflex_read_sync(s);
if (ret < 0)
return ret;
m->flags = avio_r8(pb);
if (m->flags & 2)
avio_skip(pb, 2);
}
while ((avio_tell(pb) < m->pos + m->size) && !avio_feof(pb) && avio_r8(pb)) {
int stream_index, bits, pkt_size, endframe;
AVPacket *packet;
m->in_block = 1;
avio_seek(pb, -1, SEEK_CUR);
br->pos = br->last = 0;
bits = pop_length(br, pb);
if (bits < 0)
return bits;
stream_index = pop_int(br, pb, bits);
if (stream_index < 0)
return stream_index;
if (stream_index >= s->nb_streams)
return AVERROR_INVALIDDATA;
endframe = pop(br, pb);
if (endframe < 0)
return endframe;
if (endframe) {
bits = pop_length(br, pb);
if (bits < 0)
return bits;
pop_int(br, pb, bits);
pop(br, pb);
bits = pop_length(br, pb);
if (bits < 0)
return bits;
pop_int(br, pb, bits * 2 + 26);
}
pkt_size = pop_int(br, pb, 13) + 1;
packet = s->streams[stream_index]->priv_data;
if (!packet) {
avio_skip(pb, pkt_size);
continue;
}
ret = av_append_packet(pb, packet, pkt_size);
if (ret < 0)
return ret;
if (endframe && packet->size > 0) {
av_packet_move_ref(pkt, packet);
pkt->pos = m->pos;
pkt->stream_index = stream_index;
if (s->streams[stream_index]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
pkt->duration = 1;
if (pkt->data[0] & 0x80)
pkt->flags |= AV_PKT_FLAG_KEY;
} else {
pkt->flags |= AV_PKT_FLAG_KEY;
}
return ret;
}
}
m->in_block = 0;
if (m->flags % 2 == 0) {
if (m->size <= 0)
return AVERROR_INVALIDDATA;
avio_seek(pb, m->pos + m->size, SEEK_SET);
}
}
return AVERROR_EOF;
}
static int moflex_read_seek(AVFormatContext *s, int stream_index,
int64_t pts, int flags)
{
MOFLEXDemuxContext *m = s->priv_data;
m->in_block = 0;
return -1;
}
static int moflex_read_close(AVFormatContext *s)
{
for (int i = 0; i < s->nb_streams; i++) {
AVPacket *packet = s->streams[i]->priv_data;
av_packet_free(&packet);
s->streams[i]->priv_data = 0;
}
return 0;
}
AVInputFormat ff_moflex_demuxer = {
.name = "moflex",
.long_name = NULL_IF_CONFIG_SMALL("MobiClip MOFLEX"),
.priv_data_size = sizeof(MOFLEXDemuxContext),
.read_probe = moflex_probe,
.read_header = moflex_read_header,
.read_packet = moflex_read_packet,
.read_seek = moflex_read_seek,
.read_close = moflex_read_close,
.extensions = "moflex",
.flags = AVFMT_GENERIC_INDEX,
};
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