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FFmpeg/libav/swf.c
Fabrice Bellard de6d9b6404 Initial revision 
Originally committed as revision 5 to svn://svn.ffmpeg.org/ffmpeg/trunk
2001-07-22 14:18:56 +00:00

553 lines
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C
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/*
* Flash Compatible Streaming Format
* Copyright (c) 2000 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 <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include "avformat.h"
#include <assert.h>
/* should have a generic way to indicate probable size */
#define DUMMY_FILE_SIZE (100 * 1024 * 1024)
#define DUMMY_DURATION 600 /* in seconds */
#define TAG_END 0
#define TAG_SHOWFRAME 1
#define TAG_DEFINESHAPE 2
#define TAG_FREECHARACTER 3
#define TAG_PLACEOBJECT 4
#define TAG_REMOVEOBJECT 5
#define TAG_STREAMHEAD 18
#define TAG_STREAMBLOCK 19
#define TAG_JPEG2 21
#define TAG_LONG 0x100
/* flags for shape definition */
#define FLAG_MOVETO 0x01
#define FLAG_SETFILL0 0x02
#define FLAG_SETFILL1 0x04
/* character id used */
#define BITMAP_ID 0
#define SHAPE_ID 1
typedef struct {
long long duration_pos;
long long tag_pos;
int tag;
} SWFContext;
static void put_swf_tag(AVFormatContext *s, int tag)
{
SWFContext *swf = s->priv_data;
ByteIOContext *pb = &s->pb;
swf->tag_pos = url_ftell(pb);
swf->tag = tag;
/* reserve some room for the tag */
if (tag & TAG_LONG) {
put_le16(pb, 0);
put_le32(pb, 0);
} else {
put_le16(pb, 0);
}
}
static void put_swf_end_tag(AVFormatContext *s)
{
SWFContext *swf = s->priv_data;
ByteIOContext *pb = &s->pb;
long long pos;
int tag_len, tag;
pos = url_ftell(pb);
tag_len = pos - swf->tag_pos - 2;
tag = swf->tag;
url_fseek(pb, swf->tag_pos, SEEK_SET);
if (tag & TAG_LONG) {
tag &= ~TAG_LONG;
put_le16(pb, (tag << 6) | 0x3f);
put_le32(pb, tag_len - 4);
} else {
assert(tag_len < 0x3f);
put_le16(pb, (tag << 6) | tag_len);
}
url_fseek(pb, pos, SEEK_SET);
}
static inline void max_nbits(int *nbits_ptr, int val)
{
int n;
if (val == 0)
return;
val = abs(val);
n = 1;
while (val != 0) {
n++;
val >>= 1;
}
if (n > *nbits_ptr)
*nbits_ptr = n;
}
static void put_swf_rect(ByteIOContext *pb,
int xmin, int xmax, int ymin, int ymax)
{
PutBitContext p;
UINT8 buf[256];
int nbits, mask;
init_put_bits(&p, buf, sizeof(buf), NULL, NULL);
nbits = 0;
max_nbits(&nbits, xmin);
max_nbits(&nbits, xmax);
max_nbits(&nbits, ymin);
max_nbits(&nbits, ymax);
mask = (1 << nbits) - 1;
/* rectangle info */
put_bits(&p, 5, nbits);
put_bits(&p, nbits, xmin & mask);
put_bits(&p, nbits, xmax & mask);
put_bits(&p, nbits, ymin & mask);
put_bits(&p, nbits, ymax & mask);
flush_put_bits(&p);
put_buffer(pb, buf, p.buf_ptr - p.buf);
}
static void put_swf_line_edge(PutBitContext *pb, int dx, int dy)
{
int nbits, mask;
put_bits(pb, 1, 1); /* edge */
put_bits(pb, 1, 1); /* line select */
nbits = 2;
max_nbits(&nbits, dx);
max_nbits(&nbits, dy);
mask = (1 << nbits) - 1;
put_bits(pb, 4, nbits - 2); /* 16 bits precision */
if (dx == 0) {
put_bits(pb, 1, 0);
put_bits(pb, 1, 1);
put_bits(pb, nbits, dy & mask);
} else if (dy == 0) {
put_bits(pb, 1, 0);
put_bits(pb, 1, 0);
put_bits(pb, nbits, dx & mask);
} else {
put_bits(pb, 1, 1);
put_bits(pb, nbits, dx & mask);
put_bits(pb, nbits, dy & mask);
}
}
#define FRAC_BITS 16
/* put matrix (not size optimized */
static void put_swf_matrix(ByteIOContext *pb,
int a, int b, int c, int d, int tx, int ty)
{
PutBitContext p;
UINT8 buf[256];
init_put_bits(&p, buf, sizeof(buf), NULL, NULL);
put_bits(&p, 1, 1); /* a, d present */
put_bits(&p, 5, 20); /* nb bits */
put_bits(&p, 20, a);
put_bits(&p, 20, d);
put_bits(&p, 1, 1); /* b, c present */
put_bits(&p, 5, 20); /* nb bits */
put_bits(&p, 20, c);
put_bits(&p, 20, b);
put_bits(&p, 5, 20); /* nb bits */
put_bits(&p, 20, tx);
put_bits(&p, 20, ty);
flush_put_bits(&p);
put_buffer(pb, buf, p.buf_ptr - p.buf);
}
/* XXX: handle audio only */
static int swf_write_header(AVFormatContext *s)
{
SWFContext *swf;
ByteIOContext *pb = &s->pb;
AVCodecContext *enc, *audio_enc, *video_enc;
PutBitContext p;
UINT8 buf1[256];
int i, width, height, rate;
swf = malloc(sizeof(SWFContext));
if (!swf)
return -1;
s->priv_data = swf;
video_enc = NULL;
audio_enc = NULL;
for(i=0;i<s->nb_streams;i++) {
enc = &s->streams[i]->codec;
if (enc->codec_type == CODEC_TYPE_AUDIO)
audio_enc = enc;
else
video_enc = enc;
}
if (!video_enc) {
/* currenty, cannot work correctly if audio only */
width = 320;
height = 200;
rate = 10 * FRAME_RATE_BASE;
} else {
width = video_enc->width;
height = video_enc->height;
rate = video_enc->frame_rate;
}
put_tag(pb, "FWS");
put_byte(pb, 4); /* version (should use 4 for mpeg audio support) */
put_le32(pb, DUMMY_FILE_SIZE); /* dummy size
(will be patched if not streamed) */
put_swf_rect(pb, 0, width, 0, height);
put_le16(pb, (rate * 256) / FRAME_RATE_BASE); /* frame rate */
swf->duration_pos = url_ftell(pb);
put_le16(pb, DUMMY_DURATION * (INT64)rate / FRAME_RATE_BASE); /* frame count */
/* define a shape with the jpeg inside */
put_swf_tag(s, TAG_DEFINESHAPE);
put_le16(pb, SHAPE_ID); /* ID of shape */
/* bounding rectangle */
put_swf_rect(pb, 0, width, 0, height);
/* style info */
put_byte(pb, 1); /* one fill style */
put_byte(pb, 0x41); /* clipped bitmap fill */
put_le16(pb, BITMAP_ID); /* bitmap ID */
/* position of the bitmap */
put_swf_matrix(pb, (int)(1.0 * (1 << FRAC_BITS)), 0,
0, (int)(1.0 * (1 << FRAC_BITS)), 0, 0);
put_byte(pb, 0); /* no line style */
/* shape drawing */
init_put_bits(&p, buf1, sizeof(buf1), NULL, NULL);
put_bits(&p, 4, 1); /* one fill bit */
put_bits(&p, 4, 0); /* zero line bit */
put_bits(&p, 1, 0); /* not an edge */
put_bits(&p, 5, FLAG_MOVETO | FLAG_SETFILL0);
put_bits(&p, 5, 1); /* nbits */
put_bits(&p, 1, 0); /* X */
put_bits(&p, 1, 0); /* Y */
put_bits(&p, 1, 1); /* set fill style 1 */
/* draw the rectangle ! */
put_swf_line_edge(&p, width, 0);
put_swf_line_edge(&p, 0, height);
put_swf_line_edge(&p, -width, 0);
put_swf_line_edge(&p, 0, -height);
/* end of shape */
put_bits(&p, 1, 0); /* not an edge */
put_bits(&p, 5, 0);
flush_put_bits(&p);
put_buffer(pb, buf1, p.buf_ptr - p.buf);
put_swf_end_tag(s);
if (audio_enc) {
int v;
/* start sound */
v = 0;
switch(audio_enc->sample_rate) {
case 11025:
v |= 1 << 2;
break;
case 22050:
v |= 2 << 2;
break;
case 44100:
v |= 3 << 2;
break;
default:
/* not supported */
free(swf);
return -1;
}
if (audio_enc->channels == 2)
v |= 1;
v |= 0x20; /* mp3 compressed */
v |= 0x02; /* 16 bits */
put_swf_tag(s, TAG_STREAMHEAD);
put_byte(&s->pb, 0);
put_byte(&s->pb, v);
put_le16(&s->pb, (audio_enc->sample_rate * FRAME_RATE_BASE) / rate); /* avg samples per frame */
put_swf_end_tag(s);
}
put_flush_packet(&s->pb);
return 0;
}
static int swf_write_video(AVFormatContext *s,
AVCodecContext *enc, UINT8 *buf, int size)
{
ByteIOContext *pb = &s->pb;
static int tag_id = 0;
if (enc->frame_number > 1) {
/* remove the shape */
put_swf_tag(s, TAG_REMOVEOBJECT);
put_le16(pb, SHAPE_ID); /* shape ID */
put_le16(pb, 1); /* depth */
put_swf_end_tag(s);
/* free the bitmap */
put_swf_tag(s, TAG_FREECHARACTER);
put_le16(pb, BITMAP_ID);
put_swf_end_tag(s);
}
put_swf_tag(s, TAG_JPEG2 | TAG_LONG);
put_le16(pb, tag_id); /* ID of the image */
/* a dummy jpeg header seems to be required */
put_byte(pb, 0xff);
put_byte(pb, 0xd8);
put_byte(pb, 0xff);
put_byte(pb, 0xd9);
/* write the jpeg image */
put_buffer(pb, buf, size);
put_swf_end_tag(s);
/* draw the shape */
put_swf_tag(s, TAG_PLACEOBJECT);
put_le16(pb, SHAPE_ID); /* shape ID */
put_le16(pb, 1); /* depth */
put_swf_matrix(pb, 1 << FRAC_BITS, 0, 0, 1 << FRAC_BITS, 0, 0);
put_swf_end_tag(s);
/* output the frame */
put_swf_tag(s, TAG_SHOWFRAME);
put_swf_end_tag(s);
put_flush_packet(&s->pb);
return 0;
}
static int swf_write_audio(AVFormatContext *s, UINT8 *buf, int size)
{
ByteIOContext *pb = &s->pb;
put_swf_tag(s, TAG_STREAMBLOCK | TAG_LONG);
put_buffer(pb, buf, size);
put_swf_end_tag(s);
put_flush_packet(&s->pb);
return 0;
}
static int swf_write_packet(AVFormatContext *s, int stream_index,
UINT8 *buf, int size)
{
AVCodecContext *codec = &s->streams[stream_index]->codec;
if (codec->codec_type == CODEC_TYPE_AUDIO)
return swf_write_audio(s, buf, size);
else
return swf_write_video(s, codec, buf, size);
}
static int swf_write_trailer(AVFormatContext *s)
{
SWFContext *swf = s->priv_data;
ByteIOContext *pb = &s->pb;
AVCodecContext *enc, *video_enc;
int file_size, i;
video_enc = NULL;
for(i=0;i<s->nb_streams;i++) {
enc = &s->streams[i]->codec;
if (enc->codec_type == CODEC_TYPE_VIDEO)
video_enc = enc;
}
put_swf_tag(s, TAG_END);
put_swf_end_tag(s);
put_flush_packet(&s->pb);
/* patch file size and number of frames if not streamed */
if (!url_is_streamed(&s->pb) && video_enc) {
file_size = url_ftell(pb);
url_fseek(pb, 4, SEEK_SET);
put_le32(pb, file_size);
url_fseek(pb, swf->duration_pos, SEEK_SET);
put_le16(pb, video_enc->frame_number);
}
free(swf);
return 0;
}
/***********************************/
/* just to extract MP3 from swf */
static int get_swf_tag(ByteIOContext *pb, int *len_ptr)
{
int tag, len;
if (url_feof(pb))
return -1;
tag = get_le16(pb);
len = tag & 0x3f;
tag = tag >> 6;
if (len == 0x3f) {
len = get_le32(pb);
}
*len_ptr = len;
return tag;
}
static int swf_read_header(AVFormatContext *s, AVFormatParameters *ap)
{
ByteIOContext *pb = &s->pb;
int nbits, len, frame_rate, tag, v;
AVStream *st;
if ((get_be32(pb) & 0xffffff00) != MKBETAG('F', 'W', 'S', 0))
return -EIO;
get_le32(pb);
/* skip rectangle size */
nbits = get_byte(pb) >> 3;
len = (4 * nbits - 3 + 7) / 8;
url_fskip(pb, len);
frame_rate = get_le16(pb);
get_le16(pb); /* frame count */
for(;;) {
tag = get_swf_tag(pb, &len);
if (tag < 0) {
fprintf(stderr, "No streaming found in SWF\n");
return -EIO;
}
if (tag == TAG_STREAMHEAD) {
/* streaming found */
get_byte(pb);
v = get_byte(pb);
get_le16(pb);
/* if mp3 streaming found, OK */
if ((v & 0x20) != 0) {
st = av_mallocz(sizeof(AVStream));
if (!st)
return -ENOMEM;
if (v & 0x01)
st->codec.channels = 2;
else
st->codec.channels = 1;
s->nb_streams = 1;
s->streams[0] = st;
switch((v>> 2) & 0x03) {
case 1:
st->codec.sample_rate = 11025;
break;
case 2:
st->codec.sample_rate = 22050;
break;
case 3:
st->codec.sample_rate = 44100;
break;
default:
free(st);
return -EIO;
}
st->codec.codec_type = CODEC_TYPE_AUDIO;
st->codec.codec_id = CODEC_ID_MP2;
break;
}
} else {
url_fskip(pb, len);
}
}
return 0;
}
static int swf_read_packet(AVFormatContext *s, AVPacket *pkt)
{
ByteIOContext *pb = &s->pb;
int tag, len;
for(;;) {
tag = get_swf_tag(pb, &len);
if (tag < 0)
return -EIO;
if (tag == TAG_STREAMBLOCK) {
av_new_packet(pkt, len);
get_buffer(pb, pkt->data, pkt->size);
break;
} else {
url_fskip(pb, len);
}
}
return 0;
}
static int swf_read_close(AVFormatContext *s)
{
return 0;
}
AVFormat swf_format = {
"swf",
"Flash format",
"application/x-shockwave-flash",
"swf",
CODEC_ID_MP2,
CODEC_ID_MJPEG,
swf_write_header,
swf_write_packet,
swf_write_trailer,
swf_read_header,
swf_read_packet,
swf_read_close,
};
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