RepoMirrors
/
ffmpeg
mirror of https://git.ffmpeg.org/ffmpeg.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity
ffmpeg/libav/ffm.c

651 lines
18 KiB
C
Raw Blame History

/*
* FFM (ffserver live feed) encoder and decoder
* Copyright (c) 2001 Gerard Lantau.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "avformat.h"
#include <unistd.h>
/* The FFM file is made of blocks of fixed size */
#define FFM_HEADER_SIZE 14
#define PACKET_ID 0x666d
/* each packet contains frames (which can span several packets */
#define FRAME_HEADER_SIZE 8
#define FLAG_KEY_FRAME 0x01
typedef struct FFMStream {
INT64 pts;
} FFMStream;
enum {
READ_HEADER,
READ_DATA,
};
typedef struct FFMContext {
/* only reading mode */
offset_t write_index, file_size;
int read_state;
UINT8 header[FRAME_HEADER_SIZE];
/* read and write */
int first_packet; /* true if first packet, needed to set the discontinuity tag */
int packet_size;
int frame_offset;
INT64 pts;
UINT8 *packet_ptr, *packet_end;
UINT8 packet[1]; /* must be last */
} FFMContext;
/* disable pts hack for testing */
int ffm_nopts = 0;
static void flush_packet(AVFormatContext *s)
{
FFMContext *ffm = s->priv_data;
int fill_size, h;
ByteIOContext *pb = &s->pb;
fill_size = ffm->packet_end - ffm->packet_ptr;
memset(ffm->packet_ptr, 0, fill_size);
/* put header */
put_be16(pb, PACKET_ID);
put_be16(pb, fill_size);
put_be64(pb, ffm->pts);
h = ffm->frame_offset;
if (ffm->first_packet)
h |= 0x8000;
put_be16(pb, h);
put_buffer(pb, ffm->packet, ffm->packet_end - ffm->packet);
/* prepare next packet */
ffm->frame_offset = 0; /* no key frame */
ffm->pts = 0; /* no pts */
ffm->packet_ptr = ffm->packet;
ffm->first_packet = 0;
}
/* 'first' is true if first data of a frame */
static void ffm_write_data(AVFormatContext *s,
UINT8 *buf, int size,
INT64 pts, int first)
{
FFMContext *ffm = s->priv_data;
int len;
if (first && ffm->frame_offset == 0)
ffm->frame_offset = ffm->packet_ptr - ffm->packet + FFM_HEADER_SIZE;
if (first && ffm->pts == 0)
ffm->pts = pts;
/* write as many packets as needed */
while (size > 0) {
len = ffm->packet_end - ffm->packet_ptr;
if (len > size)
len = size;
memcpy(ffm->packet_ptr, buf, len);
ffm->packet_ptr += len;
buf += len;
size -= len;
if (ffm->packet_ptr >= ffm->packet_end) {
/* special case : no pts in packet : we leave the current one */
if (ffm->pts == 0)
ffm->pts = pts;
flush_packet(s);
}
}
}
static int ffm_write_header(AVFormatContext *s)
{
FFMContext *ffm = s->priv_data;
AVStream *st;
FFMStream *fst;
ByteIOContext *pb = &s->pb;
AVCodecContext *codec;
int bit_rate, i;
ffm->packet_size = FFM_PACKET_SIZE;
/* header */
put_tag(pb, "FFM1");
put_be32(pb, ffm->packet_size);
/* XXX: store write position in other file ? */
put_be64(pb, ffm->packet_size); /* current write position */
put_be32(pb, s->nb_streams);
bit_rate = 0;
for(i=0;i<s->nb_streams;i++) {
st = s->streams[i];
bit_rate += st->codec.bit_rate;
}
put_be32(pb, bit_rate);
/* list of streams */
for(i=0;i<s->nb_streams;i++) {
st = s->streams[i];
fst = av_mallocz(sizeof(FFMStream) + ffm->packet_size);
if (!fst)
goto fail;
st->priv_data = fst;
codec = &st->codec;
/* generic info */
put_be32(pb, codec->codec_id);
put_byte(pb, codec->codec_type);
put_be32(pb, codec->bit_rate);
put_be32(pb, codec->flags);
/* specific info */
switch(codec->codec_type) {
case CODEC_TYPE_VIDEO:
put_be32(pb, (codec->frame_rate * 1000) / FRAME_RATE_BASE);
put_be16(pb, codec->width);
put_be16(pb, codec->height);
put_be16(pb, codec->gop_size);
put_byte(pb, codec->qmin);
put_byte(pb, codec->qmax);
put_byte(pb, codec->max_qdiff);
put_be16(pb, (int) (codec->qcompress * 10000.0));
put_be16(pb, (int) (codec->qblur * 10000.0));
put_be32(pb, codec->bit_rate_tolerance);
break;
case CODEC_TYPE_AUDIO:
put_be32(pb, codec->sample_rate);
put_le16(pb, codec->channels);
put_le16(pb, codec->frame_size);
break;
default:
av_abort();
}
/* hack to have real time */
if (ffm_nopts)
fst->pts = 0;
else
fst->pts = gettime();
}
/* flush until end of block reached */
while ((url_ftell(pb) % ffm->packet_size) != 0)
put_byte(pb, 0);
put_flush_packet(pb);
/* init packet mux */
ffm->packet_ptr = ffm->packet;
ffm->packet_end = ffm->packet + ffm->packet_size - FFM_HEADER_SIZE;
ffm->frame_offset = 0;
ffm->pts = 0;
ffm->first_packet = 1;
return 0;
fail:
for(i=0;i<s->nb_streams;i++) {
st = s->streams[i];
av_freep(&st->priv_data);
}
return -1;
}
static int ffm_write_packet(AVFormatContext *s, int stream_index,
UINT8 *buf, int size, int force_pts)
{
AVStream *st = s->streams[stream_index];
FFMStream *fst = st->priv_data;
INT64 pts;
UINT8 header[FRAME_HEADER_SIZE];
int duration;
if (st->codec.codec_type == CODEC_TYPE_AUDIO) {
duration = ((float)st->codec.frame_size / st->codec.sample_rate * 1000000.0);
} else {
duration = (1000000.0 * FRAME_RATE_BASE / (float)st->codec.frame_rate);
}
pts = fst->pts;
/* packet size & key_frame */
header[0] = stream_index;
header[1] = 0;
if (st->codec.key_frame)
header[1] |= FLAG_KEY_FRAME;
header[2] = (size >> 16) & 0xff;
header[3] = (size >> 8) & 0xff;
header[4] = size & 0xff;
header[5] = (duration >> 16) & 0xff;
header[6] = (duration >> 8) & 0xff;
header[7] = duration & 0xff;
ffm_write_data(s, header, FRAME_HEADER_SIZE, pts, 1);
ffm_write_data(s, buf, size, pts, 0);
fst->pts += duration;
return 0;
}
static int ffm_write_trailer(AVFormatContext *s)
{
ByteIOContext *pb = &s->pb;
FFMContext *ffm = s->priv_data;
int i;
/* flush packets */
if (ffm->packet_ptr > ffm->packet)
flush_packet(s);
put_flush_packet(pb);
for(i=0;i<s->nb_streams;i++)
av_freep(&s->streams[i]->priv_data);
return 0;
}
/* ffm demux */
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 *buf, int size, int first)
{
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 > 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->pts = 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 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 & 0x7ffff) < FFM_HEADER_SIZE)
av_abort();
ffm->packet_ptr = ffm->packet + (frame_offset & 0x7fff) - FFM_HEADER_SIZE;
if (!first)
break;
} else {
ffm->packet_ptr = ffm->packet;
}
goto redo;
}
memcpy(buf, ffm->packet_ptr, len);
buf += len;
ffm->packet_ptr += len;
size -= len;
first = 0;
}
return size1 - size;
}
static int ffm_read_header(AVFormatContext *s, AVFormatParameters *ap)
{
FFMContext *ffm = s->priv_data;
AVStream *st;
FFMStream *fst;
ByteIOContext *pb = &s->pb;
AVCodecContext *codec;
int i;
UINT32 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_filesize(url_fileno(pb));
} else {
ffm->file_size = (UINT64_C(1) << 63) - 1;
}
s->nb_streams = get_be32(pb);
get_be32(pb); /* total bitrate */
/* read each stream */
for(i=0;i<s->nb_streams;i++) {
st = av_mallocz(sizeof(AVStream));
if (!st)
goto fail;
s->streams[i] = st;
fst = av_mallocz(sizeof(FFMStream) + ffm->packet_size);
if (!fst)
goto fail;
st->priv_data = fst;
codec = &st->codec;
/* generic info */
st->codec.codec_id = get_be32(pb);
st->codec.codec_type = get_byte(pb); /* codec_type */
codec->bit_rate = get_be32(pb);
codec->flags = get_be32(pb);
/* specific info */
switch(codec->codec_type) {
case CODEC_TYPE_VIDEO:
codec->frame_rate = ((INT64)get_be32(pb) * FRAME_RATE_BASE) / 1000;
codec->width = get_be16(pb);
codec->height = get_be16(pb);
codec->gop_size = get_be16(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);
break;
case CODEC_TYPE_AUDIO:
codec->sample_rate = get_be32(pb);
codec->channels = get_le16(pb);
codec->frame_size = get_le16(pb);
break;
default:
av_abort();
}
}
/* 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->pts = 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_freep(&st->priv_data);
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))
return -EAGAIN;
#if 0
printf("pos=%08Lx spos=%Lx, write_index=%Lx size=%Lx\n",
url_ftell(&s->pb), s->pb.pos, ffm->write_index, ffm->file_size);
#endif
if (ffm_read_data(s, ffm->header, FRAME_HEADER_SIZE, 1) != FRAME_HEADER_SIZE)
return -EAGAIN;
#if 0
{
int i;
for(i=0;i<FRAME_HEADER_SIZE;i++)
printf("%02x ", ffm->header[i]);
printf("\n");
}
#endif
ffm->read_state = READ_DATA;
/* fall thru */
case READ_DATA:
size = (ffm->header[2] << 16) | (ffm->header[3] << 8) | ffm->header[4];
if (!ffm_is_avail_data(s, size)) {
return -EAGAIN;
}
duration = (ffm->header[5] << 16) | (ffm->header[6] << 8) | ffm->header[7];
av_new_packet(pkt, size);
pkt->stream_index = ffm->header[0];
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 -EAGAIN;
}
pkt->pts = ffm->pts;
pkt->duration = duration;
break;
}
return 0;
}
//#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
printf("seek to %Lx -> %Lx\n", pos1, pos);
#endif
url_fseek(pb, pos, SEEK_SET);
}
static INT64 get_pts(AVFormatContext *s, offset_t pos)
{
ByteIOContext *pb = &s->pb;
INT64 pts;
ffm_seek1(s, pos);
url_fskip(pb, 4);
pts = get_be64(pb);
#ifdef DEBUG_SEEK
printf("pts=%0.6f\n", pts / 1000000.0);
#endif
return pts;
}
/* seek to a given time in the file. The file read pointer is
positionned at or before pts. XXX: the following code is quite
approximative */
static int ffm_seek(AVFormatContext *s, INT64 wanted_pts)
{
FFMContext *ffm = s->priv_data;
offset_t pos_min, pos_max, pos;
INT64 pts_min, pts_max, pts;
double pos1;
#ifdef DEBUG_SEEK
printf("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_pts(s, pos_min);
pts_max = get_pts(s, pos_max);
/* linear interpolation */
pos1 = (double)(pos_max - pos_min) * (double)(wanted_pts - pts_min) /
(double)(pts_max - pts_min);
pos = (((INT64)pos1) / FFM_PACKET_SIZE) * FFM_PACKET_SIZE;
if (pos <= pos_min)
pos = pos_min;
else if (pos >= pos_max)
pos = pos_max;
pts = get_pts(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 = pos_min;
if (pos > 0)
pos -= FFM_PACKET_SIZE;
found:
ffm_seek1(s, pos);
return 0;
}
offset_t ffm_read_write_index(int fd)
{
UINT8 buf[8];
offset_t pos;
int i;
lseek(fd, 8, SEEK_SET);
read(fd, buf, 8);
pos = 0;
for(i=0;i<8;i++)
pos |= buf[i] << (56 - i * 8);
return pos;
}
void ffm_write_write_index(int fd, offset_t pos)
{
UINT8 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;
}
static int ffm_read_close(AVFormatContext *s)
{
AVStream *st;
int i;
for(i=0;i<s->nb_streams;i++) {
st = s->streams[i];
av_freep(&st->priv_data);
}
av_freep(&s->priv_data);
return 0;
}
static int ffm_probe(AVProbeData *p)
{
if (memcmp(p->buf, "FFM", 3) == 0)
return AVPROBE_SCORE_MAX + 1;
return 0;
}
AVInputFormat ffm_iformat = {
"ffm",
"ffm format",
sizeof(FFMContext) + FFM_PACKET_SIZE,
ffm_probe,
ffm_read_header,
ffm_read_packet,
ffm_read_close,
ffm_seek,
extensions: "ffm",
};
AVOutputFormat ffm_oformat = {
"ffm",
"ffm format",
"",
"ffm",
sizeof(FFMContext) + FFM_PACKET_SIZE,
/* not really used */
CODEC_ID_MP2,
CODEC_ID_MPEG1VIDEO,
ffm_write_header,
ffm_write_packet,
ffm_write_trailer,
};
int ffm_init(void)
{
av_register_input_format(&ffm_iformat);
av_register_output_format(&ffm_oformat);
return 0;
}
Reference in New Issue View Git Blame Copy Permalink