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ffmpeg/libavformat/sierravmd.c

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/*
* Sierra VMD Format Demuxer
* Copyright (c) 2004 The ffmpeg Project
*
* This library 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 of the License, or (at your option) any later version.
*
* This library 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 this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file sierravmd.c
* Sierra VMD file demuxer
* by Vladimir "VAG" Gneushev (vagsoft at mail.ru)
* for more information on the Sierra VMD file format, visit:
* http://www.pcisys.net/~melanson/codecs/
*/
#include "avformat.h"
#define VMD_HEADER_SIZE 0x0330
#define BYTES_PER_FRAME_RECORD 16
typedef struct {
int stream_index;
offset_t frame_offset;
unsigned int frame_size;
int64_t pts;
int keyframe;
unsigned char frame_record[BYTES_PER_FRAME_RECORD];
} vmd_frame_t;
typedef struct VmdDemuxContext {
int video_stream_index;
int audio_stream_index;
unsigned int audio_type;
unsigned int audio_samplerate;
unsigned int audio_bits;
unsigned int audio_channels;
unsigned int frame_count;
vmd_frame_t *frame_table;
unsigned int current_frame;
int sample_rate;
int64_t audio_sample_counter;
int audio_frame_divisor;
int audio_block_align;
unsigned char vmd_header[VMD_HEADER_SIZE];
} VmdDemuxContext;
static int vmd_probe(AVProbeData *p)
{
if (p->buf_size < 2)
return 0;
/* check if the first 2 bytes of the file contain the appropriate size
* of a VMD header chunk */
if (LE_16(&p->buf[0]) != VMD_HEADER_SIZE - 2)
return 0;
/* only return half certainty since this check is a bit sketchy */
return AVPROBE_SCORE_MAX / 2;
}
/* This is a support function to determine the duration, in sample
* frames, of a particular audio chunk, taking into account silent
* encodings. */
static int vmd_calculate_audio_duration(unsigned char *audio_chunk,
int audio_chunk_size, int block_align)
{
unsigned char *p = audio_chunk + 16;
unsigned char *p_end = audio_chunk + audio_chunk_size;
int total_samples = 0;
unsigned int sound_flags;
if (audio_chunk_size < 16)
return 0;
sound_flags = LE_32(p);
p += 4;
while (p < p_end) {
total_samples += block_align;
if ((sound_flags & 0x01) == 0)
p += block_align;
sound_flags >>= 1;
}
return total_samples;
}
static int vmd_read_header(AVFormatContext *s,
AVFormatParameters *ap)
{
VmdDemuxContext *vmd = (VmdDemuxContext *)s->priv_data;
ByteIOContext *pb = &s->pb;
AVStream *st;
unsigned int toc_offset;
unsigned char *raw_frame_table;
int raw_frame_table_size;
unsigned char *current_frame_record;
offset_t current_offset;
int i;
unsigned int total_frames;
int64_t video_pts_inc;
int64_t current_video_pts = 0;
/* fetch the main header, including the 2 header length bytes */
url_fseek(pb, 0, SEEK_SET);
if (get_buffer(pb, vmd->vmd_header, VMD_HEADER_SIZE) != VMD_HEADER_SIZE)
return AVERROR_IO;
vmd->audio_sample_counter = 0;
vmd->audio_frame_divisor = 1;
vmd->audio_block_align = 1;
/* start up the decoders */
st = av_new_stream(s, 0);
if (!st)
return AVERROR_NOMEM;
av_set_pts_info(st, 33, 1, 90000);
vmd->video_stream_index = st->index;
st->codec->codec_type = CODEC_TYPE_VIDEO;
st->codec->codec_id = CODEC_ID_VMDVIDEO;
st->codec->codec_tag = 0; /* no fourcc */
st->codec->width = LE_16(&vmd->vmd_header[12]);
st->codec->height = LE_16(&vmd->vmd_header[14]);
st->codec->extradata_size = VMD_HEADER_SIZE;
st->codec->extradata = av_mallocz(VMD_HEADER_SIZE + FF_INPUT_BUFFER_PADDING_SIZE);
memcpy(st->codec->extradata, vmd->vmd_header, VMD_HEADER_SIZE);
/* if sample rate is 0, assume no audio */
vmd->sample_rate = LE_16(&vmd->vmd_header[804]);
if (vmd->sample_rate) {
st = av_new_stream(s, 0);
if (!st)
return AVERROR_NOMEM;
av_set_pts_info(st, 33, 1, 90000);
vmd->audio_stream_index = st->index;
st->codec->codec_type = CODEC_TYPE_AUDIO;
st->codec->codec_id = CODEC_ID_VMDAUDIO;
st->codec->codec_tag = 0; /* no codec tag */
st->codec->channels = (vmd->vmd_header[811] & 0x80) ? 2 : 1;
st->codec->sample_rate = vmd->sample_rate;
st->codec->block_align = vmd->audio_block_align =
LE_16(&vmd->vmd_header[806]);
if (st->codec->block_align & 0x8000) {
st->codec->bits_per_sample = 16;
st->codec->block_align = -(st->codec->block_align - 0x10000);
} else
st->codec->bits_per_sample = 16;
// st->codec->bits_per_sample = 8;
st->codec->bit_rate = st->codec->sample_rate *
st->codec->bits_per_sample * st->codec->channels;
/* for calculating pts */
vmd->audio_frame_divisor = st->codec->bits_per_sample / 8 /
st->codec->channels;
video_pts_inc = 90000;
video_pts_inc *= st->codec->block_align;
video_pts_inc /= st->codec->sample_rate;
} else {
/* if no audio, assume 10 frames/second */
video_pts_inc = 90000 / 10;
}
/* skip over the offset table and load the table of contents; don't
* care about the offset table since demuxer will calculate those
* independently */
toc_offset = LE_32(&vmd->vmd_header[812]);
vmd->frame_count = LE_16(&vmd->vmd_header[6]);
url_fseek(pb, toc_offset + vmd->frame_count * 6, SEEK_SET);
/* each on-disk VMD frame has an audio part and a video part; demuxer
* accounts them separately */
if(vmd->sample_rate)
vmd->frame_count *= 2;
raw_frame_table = NULL;
vmd->frame_table = NULL;
raw_frame_table_size = vmd->frame_count * BYTES_PER_FRAME_RECORD;
raw_frame_table = av_malloc(raw_frame_table_size);
vmd->frame_table = av_malloc(vmd->frame_count * sizeof(vmd_frame_t));
if (!raw_frame_table || !vmd->frame_table) {
av_free(raw_frame_table);
av_free(vmd->frame_table);
return AVERROR_NOMEM;
}
if (get_buffer(pb, raw_frame_table, raw_frame_table_size) !=
raw_frame_table_size) {
av_free(raw_frame_table);
av_free(vmd->frame_table);
return AVERROR_IO;
}
current_offset = LE_32(&vmd->vmd_header[20]);
current_frame_record = raw_frame_table;
total_frames = vmd->frame_count;
i = 0;
while (total_frames--) {
/* if the frame size is 0, do not count the frame and bring the
* total frame count down */
// note, we limit the size to 1Gb to ensure that we dont end up overflowing the size integer used to allocate the memory
vmd->frame_table[i].frame_size = LE_32(&current_frame_record[2]) & 0x3FFFFFFF;
/* this logic is present so that 0-length audio chunks are not
* accounted */
if (!vmd->frame_table[i].frame_size) {
vmd->frame_count--; /* one less frame to count */
current_frame_record += BYTES_PER_FRAME_RECORD;
continue;
}
if (current_frame_record[0] == 0x02)
vmd->frame_table[i].stream_index = vmd->video_stream_index;
else
vmd->frame_table[i].stream_index = vmd->audio_stream_index;
vmd->frame_table[i].frame_offset = current_offset;
current_offset += vmd->frame_table[i].frame_size;
memcpy(vmd->frame_table[i].frame_record, current_frame_record,
BYTES_PER_FRAME_RECORD);
/* figure out the pts for this frame */
if (current_frame_record[0] == 0x02) {
vmd->frame_table[i].pts = current_video_pts;
current_video_pts += video_pts_inc;
} else if (current_frame_record[0] == 0x01) {
/* figure out the pts during the dispatch phase */
vmd->frame_table[i].pts = 0;
}
current_frame_record += BYTES_PER_FRAME_RECORD;
i++;
}
av_free(raw_frame_table);
vmd->current_frame = 0;
return 0;
}
static int vmd_read_packet(AVFormatContext *s,
AVPacket *pkt)
{
VmdDemuxContext *vmd = (VmdDemuxContext *)s->priv_data;
ByteIOContext *pb = &s->pb;
int ret = 0;
vmd_frame_t *frame;
if (vmd->current_frame >= vmd->frame_count)
return AVERROR_IO;
frame = &vmd->frame_table[vmd->current_frame];
/* position the stream (will probably be there already) */
url_fseek(pb, frame->frame_offset, SEEK_SET);
if (av_new_packet(pkt, frame->frame_size + BYTES_PER_FRAME_RECORD))
return AVERROR_NOMEM;
pkt->pos= url_ftell(pb);
memcpy(pkt->data, frame->frame_record, BYTES_PER_FRAME_RECORD);
ret = get_buffer(pb, pkt->data + BYTES_PER_FRAME_RECORD,
frame->frame_size);
if (ret != frame->frame_size) {
av_free_packet(pkt);
ret = AVERROR_IO;
}
pkt->stream_index = frame->stream_index;
if (frame->frame_record[0] == 0x02)
pkt->pts = frame->pts;
else {
pkt->pts = vmd->audio_sample_counter;
pkt->pts *= 90000;
pkt->pts /= vmd->sample_rate;
// pkt->pts /= vmd->audio_frame_divisor;
vmd->audio_sample_counter += vmd_calculate_audio_duration(
pkt->data, pkt->size, vmd->audio_block_align);
}
av_log(NULL, AV_LOG_INFO, " dispatching %s frame with %d bytes and pts %"PRId64" (%0.1f sec)\n",
(frame->frame_record[0] == 0x02) ? "video" : "audio",
frame->frame_size + BYTES_PER_FRAME_RECORD,
pkt->pts, (float)(pkt->pts / 90000.0));
vmd->current_frame++;
return ret;
}
static int vmd_read_close(AVFormatContext *s)
{
VmdDemuxContext *vmd = (VmdDemuxContext *)s->priv_data;
av_free(vmd->frame_table);
return 0;
}
static AVInputFormat vmd_iformat = {
"vmd",
"Sierra VMD format",
sizeof(VmdDemuxContext),
vmd_probe,
vmd_read_header,
vmd_read_packet,
vmd_read_close,
};
int vmd_init(void)
{
av_register_input_format(&vmd_iformat);
return 0;
}
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