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ffmpeg/libavformat/ffmdec.c

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/*
* FFM (ffserver live feed) demuxer
* Copyright (c) 2001 Fabrice Bellard.
*
* 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 "avformat.h"
#include "ffm.h"
#ifdef CONFIG_FFSERVER
#include <unistd.h>
offset_t ffm_read_write_index(int fd)
{
uint8_t buf[8];
lseek(fd, 8, SEEK_SET);
read(fd, buf, 8);
return AV_RB64(buf);
}
void ffm_write_write_index(int fd, offset_t pos)
{
uint8_t buf[8];
int i;
for(i=0;i<8;i++)
buf[i] = (pos >> (56 - i * 8)) & 0xff;
lseek(fd, 8, SEEK_SET);
write(fd, buf, 8);
}
void ffm_set_write_index(AVFormatContext *s, offset_t pos, offset_t file_size)
{
FFMContext *ffm = s->priv_data;
ffm->write_index = pos;
ffm->file_size = file_size;
}
#endif // CONFIG_FFSERVER
static int ffm_is_avail_data(AVFormatContext *s, int size)
{
FFMContext *ffm = s->priv_data;
offset_t pos, avail_size;
int len;
len = ffm->packet_end - ffm->packet_ptr;
if (size <= len)
return 1;
pos = url_ftell(s->pb);
if (pos == ffm->write_index) {
/* exactly at the end of stream */
return 0;
} else if (pos < ffm->write_index) {
avail_size = ffm->write_index - pos;
} else {
avail_size = (ffm->file_size - pos) + (ffm->write_index - FFM_PACKET_SIZE);
}
avail_size = (avail_size / ffm->packet_size) * (ffm->packet_size - FFM_HEADER_SIZE) + len;
if (size <= avail_size)
return 1;
else
return 0;
}
/* first is true if we read the frame header */
static int ffm_read_data(AVFormatContext *s,
uint8_t *buf, int size, int header)
{
FFMContext *ffm = s->priv_data;
ByteIOContext *pb = s->pb;
int len, fill_size, size1, frame_offset;
size1 = size;
while (size > 0) {
redo:
len = ffm->packet_end - ffm->packet_ptr;
if (len < 0)
return -1;
if (len > size)
len = size;
if (len == 0) {
if (url_ftell(pb) == ffm->file_size)
url_fseek(pb, ffm->packet_size, SEEK_SET);
retry_read:
get_be16(pb); /* PACKET_ID */
fill_size = get_be16(pb);
ffm->dts = get_be64(pb);
frame_offset = get_be16(pb);
get_buffer(pb, ffm->packet, ffm->packet_size - FFM_HEADER_SIZE);
ffm->packet_end = ffm->packet + (ffm->packet_size - FFM_HEADER_SIZE - fill_size);
if (ffm->packet_end < ffm->packet || frame_offset < 0)
return -1;
/* if first packet or resynchronization packet, we must
handle it specifically */
if (ffm->first_packet || (frame_offset & 0x8000)) {
if (!frame_offset) {
/* This packet has no frame headers in it */
if (url_ftell(pb) >= ffm->packet_size * 3) {
url_fseek(pb, -ffm->packet_size * 2, SEEK_CUR);
goto retry_read;
}
/* This is bad, we cannot find a valid frame header */
return 0;
}
ffm->first_packet = 0;
if ((frame_offset & 0x7fff) < FFM_HEADER_SIZE)
return -1;
ffm->packet_ptr = ffm->packet + (frame_offset & 0x7fff) - FFM_HEADER_SIZE;
if (!header)
break;
} else {
ffm->packet_ptr = ffm->packet;
}
goto redo;
}
memcpy(buf, ffm->packet_ptr, len);
buf += len;
ffm->packet_ptr += len;
size -= len;
header = 0;
}
return size1 - size;
}
//#define DEBUG_SEEK
/* pos is between 0 and file_size - FFM_PACKET_SIZE. It is translated
by the write position inside this function */
static void ffm_seek1(AVFormatContext *s, offset_t pos1)
{
FFMContext *ffm = s->priv_data;
ByteIOContext *pb = s->pb;
offset_t pos;
pos = pos1 + ffm->write_index;
if (pos >= ffm->file_size)
pos -= (ffm->file_size - FFM_PACKET_SIZE);
#ifdef DEBUG_SEEK
av_log(s, AV_LOG_DEBUG, "seek to %"PRIx64" -> %"PRIx64"\n", pos1, pos);
#endif
url_fseek(pb, pos, SEEK_SET);
}
static int64_t get_dts(AVFormatContext *s, offset_t pos)
{
ByteIOContext *pb = s->pb;
int64_t dts;
ffm_seek1(s, pos);
url_fskip(pb, 4);
dts = get_be64(pb);
#ifdef DEBUG_SEEK
av_log(s, AV_LOG_DEBUG, "pts=%0.6f\n", pts / 1000000.0);
#endif
return dts;
}
static void adjust_write_index(AVFormatContext *s)
{
FFMContext *ffm = s->priv_data;
ByteIOContext *pb = s->pb;
int64_t pts;
//offset_t orig_write_index = ffm->write_index;
offset_t pos_min, pos_max;
int64_t pts_start;
offset_t ptr = url_ftell(pb);
pos_min = 0;
pos_max = ffm->file_size - 2 * FFM_PACKET_SIZE;
pts_start = get_dts(s, pos_min);
pts = get_dts(s, pos_max);
if (pts - 100000 > pts_start)
goto end;
ffm->write_index = FFM_PACKET_SIZE;
pts_start = get_dts(s, pos_min);
pts = get_dts(s, pos_max);
if (pts - 100000 <= pts_start) {
while (1) {
offset_t newpos;
int64_t newpts;
newpos = ((pos_max + pos_min) / (2 * FFM_PACKET_SIZE)) * FFM_PACKET_SIZE;
if (newpos == pos_min)
break;
newpts = get_dts(s, newpos);
if (newpts - 100000 <= pts) {
pos_max = newpos;
pts = newpts;
} else {
pos_min = newpos;
}
}
ffm->write_index += pos_max;
}
//printf("Adjusted write index from %"PRId64" to %"PRId64": pts=%0.6f\n", orig_write_index, ffm->write_index, pts / 1000000.);
//printf("pts range %0.6f - %0.6f\n", get_dts(s, 0) / 1000000. , get_dts(s, ffm->file_size - 2 * FFM_PACKET_SIZE) / 1000000. );
end:
url_fseek(pb, ptr, SEEK_SET);
}
static int ffm_read_header(AVFormatContext *s, AVFormatParameters *ap)
{
FFMContext *ffm = s->priv_data;
AVStream *st;
ByteIOContext *pb = s->pb;
AVCodecContext *codec;
int i, nb_streams;
uint32_t tag;
/* header */
tag = get_le32(pb);
if (tag != MKTAG('F', 'F', 'M', '1'))
goto fail;
ffm->packet_size = get_be32(pb);
if (ffm->packet_size != FFM_PACKET_SIZE)
goto fail;
ffm->write_index = get_be64(pb);
/* get also filesize */
if (!url_is_streamed(pb)) {
ffm->file_size = url_fsize(pb);
adjust_write_index(s);
} else {
ffm->file_size = (UINT64_C(1) << 63) - 1;
}
nb_streams = get_be32(pb);
get_be32(pb); /* total bitrate */
/* read each stream */
for(i=0;i<nb_streams;i++) {
char rc_eq_buf[128];
st = av_new_stream(s, 0);
if (!st)
goto fail;
s->streams[i] = st;
av_set_pts_info(st, 64, 1, 1000000);
codec = st->codec;
/* generic info */
codec->codec_id = get_be32(pb);
codec->codec_type = get_byte(pb); /* codec_type */
codec->bit_rate = get_be32(pb);
st->quality = get_be32(pb);
codec->flags = get_be32(pb);
codec->flags2 = get_be32(pb);
codec->debug = get_be32(pb);
/* specific info */
switch(codec->codec_type) {
case CODEC_TYPE_VIDEO:
codec->time_base.num = get_be32(pb);
codec->time_base.den = get_be32(pb);
codec->width = get_be16(pb);
codec->height = get_be16(pb);
codec->gop_size = get_be16(pb);
codec->pix_fmt = get_be32(pb);
codec->qmin = get_byte(pb);
codec->qmax = get_byte(pb);
codec->max_qdiff = get_byte(pb);
codec->qcompress = get_be16(pb) / 10000.0;
codec->qblur = get_be16(pb) / 10000.0;
codec->bit_rate_tolerance = get_be32(pb);
codec->rc_eq = av_strdup(get_strz(pb, rc_eq_buf, sizeof(rc_eq_buf)));
codec->rc_max_rate = get_be32(pb);
codec->rc_min_rate = get_be32(pb);
codec->rc_buffer_size = get_be32(pb);
codec->i_quant_factor = av_int2dbl(get_be64(pb));
codec->b_quant_factor = av_int2dbl(get_be64(pb));
codec->i_quant_offset = av_int2dbl(get_be64(pb));
codec->b_quant_offset = av_int2dbl(get_be64(pb));
codec->dct_algo = get_be32(pb);
codec->strict_std_compliance = get_be32(pb);
codec->max_b_frames = get_be32(pb);
codec->luma_elim_threshold = get_be32(pb);
codec->chroma_elim_threshold = get_be32(pb);
codec->mpeg_quant = get_be32(pb);
codec->intra_dc_precision = get_be32(pb);
codec->me_method = get_be32(pb);
codec->mb_decision = get_be32(pb);
codec->nsse_weight = get_be32(pb);
codec->frame_skip_cmp = get_be32(pb);
codec->rc_buffer_aggressivity = av_int2dbl(get_be64(pb));
codec->codec_tag = get_be32(pb);
codec->thread_count = get_byte(pb);
break;
case CODEC_TYPE_AUDIO:
codec->sample_rate = get_be32(pb);
codec->channels = get_le16(pb);
codec->frame_size = get_le16(pb);
break;
default:
goto fail;
}
if (codec->flags & CODEC_FLAG_GLOBAL_HEADER) {
codec->extradata_size = get_be32(pb);
codec->extradata = av_malloc(codec->extradata_size);
if (!codec->extradata)
return AVERROR(ENOMEM);
get_buffer(pb, codec->extradata, codec->extradata_size);
}
}
/* get until end of block reached */
while ((url_ftell(pb) % ffm->packet_size) != 0)
get_byte(pb);
/* init packet demux */
ffm->packet_ptr = ffm->packet;
ffm->packet_end = ffm->packet;
ffm->frame_offset = 0;
ffm->dts = 0;
ffm->read_state = READ_HEADER;
ffm->first_packet = 1;
return 0;
fail:
for(i=0;i<s->nb_streams;i++) {
st = s->streams[i];
if (st) {
av_free(st);
}
}
return -1;
}
/* return < 0 if eof */
static int ffm_read_packet(AVFormatContext *s, AVPacket *pkt)
{
int size;
FFMContext *ffm = s->priv_data;
int duration;
switch(ffm->read_state) {
case READ_HEADER:
if (!ffm_is_avail_data(s, FRAME_HEADER_SIZE+4)) {
return AVERROR(EAGAIN);
}
dprintf(s, "pos=%08"PRIx64" spos=%"PRIx64", write_index=%"PRIx64" size=%"PRIx64"\n",
url_ftell(s->pb), s->pb->pos, ffm->write_index, ffm->file_size);
if (ffm_read_data(s, ffm->header, FRAME_HEADER_SIZE, 1) !=
FRAME_HEADER_SIZE)
return AVERROR(EAGAIN);
if (ffm->header[1] & FLAG_DTS)
if (ffm_read_data(s, ffm->header+16, 4, 1) != 4)
return AVERROR(EAGAIN);
#if 0
av_hexdump_log(s, AV_LOG_DEBUG, ffm->header, FRAME_HEADER_SIZE);
#endif
ffm->read_state = READ_DATA;
/* fall thru */
case READ_DATA:
size = AV_RB24(ffm->header + 2);
if (!ffm_is_avail_data(s, size)) {
return AVERROR(EAGAIN);
}
duration = AV_RB24(ffm->header + 5);
av_new_packet(pkt, size);
pkt->stream_index = ffm->header[0];
if ((unsigned)pkt->stream_index >= s->nb_streams) {
av_log(s, AV_LOG_ERROR, "invalid stream index %d\n", pkt->stream_index);
av_free_packet(pkt);
ffm->read_state = READ_HEADER;
return AVERROR(EAGAIN);
}
pkt->pos = url_ftell(s->pb);
if (ffm->header[1] & FLAG_KEY_FRAME)
pkt->flags |= PKT_FLAG_KEY;
ffm->read_state = READ_HEADER;
if (ffm_read_data(s, pkt->data, size, 0) != size) {
/* bad case: desynchronized packet. we cancel all the packet loading */
av_free_packet(pkt);
return AVERROR(EAGAIN);
}
pkt->pts = AV_RB64(ffm->header+8);
if (ffm->header[1] & FLAG_DTS)
pkt->dts = pkt->pts - AV_RB32(ffm->header+16);
else
pkt->dts = pkt->pts;
pkt->duration = duration;
break;
}
return 0;
}
/* seek to a given time in the file. The file read pointer is
positioned at or before pts. XXX: the following code is quite
approximative */
static int ffm_seek(AVFormatContext *s, int stream_index, int64_t wanted_pts, int flags)
{
FFMContext *ffm = s->priv_data;
offset_t pos_min, pos_max, pos;
int64_t pts_min, pts_max, pts;
double pos1;
#ifdef DEBUG_SEEK
av_log(s, AV_LOG_DEBUG, "wanted_pts=%0.6f\n", wanted_pts / 1000000.0);
#endif
/* find the position using linear interpolation (better than
dichotomy in typical cases) */
pos_min = 0;
pos_max = ffm->file_size - 2 * FFM_PACKET_SIZE;
while (pos_min <= pos_max) {
pts_min = get_dts(s, pos_min);
pts_max = get_dts(s, pos_max);
/* linear interpolation */
pos1 = (double)(pos_max - pos_min) * (double)(wanted_pts - pts_min) /
(double)(pts_max - pts_min);
pos = (((int64_t)pos1) / FFM_PACKET_SIZE) * FFM_PACKET_SIZE;
if (pos <= pos_min)
pos = pos_min;
else if (pos >= pos_max)
pos = pos_max;
pts = get_dts(s, pos);
/* check if we are lucky */
if (pts == wanted_pts) {
goto found;
} else if (pts > wanted_pts) {
pos_max = pos - FFM_PACKET_SIZE;
} else {
pos_min = pos + FFM_PACKET_SIZE;
}
}
pos = (flags & AVSEEK_FLAG_BACKWARD) ? pos_min : pos_max;
if (pos > 0)
pos -= FFM_PACKET_SIZE;
found:
ffm_seek1(s, pos);
/* reset read state */
ffm->read_state = READ_HEADER;
ffm->packet_ptr = ffm->packet;
ffm->packet_end = ffm->packet;
ffm->first_packet = 1;
return 0;
}
static int ffm_probe(AVProbeData *p)
{
if (
p->buf[0] == 'F' && p->buf[1] == 'F' && p->buf[2] == 'M' &&
p->buf[3] == '1')
return AVPROBE_SCORE_MAX + 1;
return 0;
}
AVInputFormat ffm_demuxer = {
"ffm",
NULL_IF_CONFIG_SMALL("ffm format"),
sizeof(FFMContext),
ffm_probe,
ffm_read_header,
ffm_read_packet,
NULL,
ffm_seek,
};
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