swf.c

FFmpeg is an audio/video conversion tool. It includes libavcodec, the leading open source codec libr

/*
 * Flash Compatible Streaming Format
 * Copyright (c) 2000 Fabrice Bellard.
 * Copyright (c) 2003 Tinic Uro.
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
#include "avformat.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    45
#define TAG_STREAMBLOCK   19
#define TAG_JPEG2         21
#define TAG_PLACEOBJECT2  26
#define TAG_STREAMHEAD2   45
#define TAG_VIDEOSTREAM	  60
#define TAG_VIDEOFRAME    61

#define TAG_LONG         0x100

/* flags for shape definition */
#define FLAG_MOVETO      0x01
#define FLAG_SETFILL0    0x02
#define FLAG_SETFILL1    0x04

#define SWF_VIDEO_CODEC_FLV1	0x02

#define AUDIO_FIFO_SIZE 65536

/* character id used */
#define BITMAP_ID 0
#define VIDEO_ID 0
#define SHAPE_ID  1

typedef struct SWFFrame_s {
    void *data;
    int size;
    struct SWFFrame_s *prev;
    struct SWFFrame_s *next;
} SWFFrame;

typedef struct {

    offset_t duration_pos;
    offset_t tag_pos;
    
    int samples_per_frame;
    int sound_samples;
    int video_samples;
    int skip_samples;
    int swf_frame_number;
    int video_frame_number;
    int ms_per_frame;
    int ch_id;
    int tag;

    uint8_t *audio_fifo;
    int audio_in_pos;
    int audio_out_pos;
    int audio_size;

    int video_type;
    int audio_type;
    
    SWFFrame *frame_head;
    SWFFrame *frame_tail;
} SWFContext;

static const int sSampleRates[3][4] = {
    {44100, 48000, 32000, 0},
    {22050, 24000, 16000, 0},
    {11025, 12000,  8000, 0},
};

static const int sBitRates[2][3][15] = {
    {   {  0, 32, 64, 96,128,160,192,224,256,288,320,352,384,416,448},
        {  0, 32, 48, 56, 64, 80, 96,112,128,160,192,224,256,320,384},
        {  0, 32, 40, 48, 56, 64, 80, 96,112,128,160,192,224,256,320}
    },
    {   {  0, 32, 48, 56, 64, 80, 96,112,128,144,160,176,192,224,256},
        {  0,  8, 16, 24, 32, 40, 48, 56, 64, 80, 96,112,128,144,160},
        {  0,  8, 16, 24, 32, 40, 48, 56, 64, 80, 96,112,128,144,160}
    },
};

static const int sSamplesPerFrame[3][3] =
{
    {  384,     1152,    1152 },
    {  384,     1152,     576 },
    {  384,     1152,     576 }
};

static const int sBitsPerSlot[3] = {
    32,
    8,
    8
};

static int swf_mp3_info(void *data, int *byteSize, int *samplesPerFrame, int *sampleRate, int *isMono )
{
    uint8_t *dataTmp = (uint8_t *)data;
    uint32_t header = ( (uint32_t)dataTmp[0] << 24 ) | ( (uint32_t)dataTmp[1] << 16 ) | ( (uint32_t)dataTmp[2] << 8 ) | (uint32_t)dataTmp[3];
    int layerID = 3 - ((header >> 17) & 0x03);
    int bitRateID = ((header >> 12) & 0x0f);
    int sampleRateID = ((header >> 10) & 0x03);
    int bitRate = 0;
    int bitsPerSlot = sBitsPerSlot[layerID];
    int isPadded = ((header >> 9) & 0x01);
    
    if ( (( header >> 21 ) & 0x7ff) != 0x7ff ) {
        return 0;
    }

    *isMono = ((header >>  6) & 0x03) == 0x03;

    if ( (header >> 19 ) & 0x01 ) {
        *sampleRate = sSampleRates[0][sampleRateID];
        bitRate = sBitRates[0][layerID][bitRateID] * 1000;
        *samplesPerFrame = sSamplesPerFrame[0][layerID];
    } else {
        if ( (header >> 20) & 0x01 ) {
            *sampleRate = sSampleRates[1][sampleRateID];
            bitRate = sBitRates[1][layerID][bitRateID] * 1000;
            *samplesPerFrame = sSamplesPerFrame[1][layerID];
        } else {
            *sampleRate = sSampleRates[2][sampleRateID];
            bitRate = sBitRates[1][layerID][bitRateID] * 1000;
            *samplesPerFrame = sSamplesPerFrame[2][layerID];
        }
    }

    *byteSize = ( ( ( ( *samplesPerFrame * (bitRate / bitsPerSlot) ) / *sampleRate ) + isPadded ) );

    return 1;
}

#ifdef CONFIG_ENCODERS
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;
    offset_t 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_t buf[256];
    int nbits, mask;

    init_put_bits(&p, buf, sizeof(buf));
    
    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, pbBufPtr(&p) - 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 */
static void put_swf_matrix(ByteIOContext *pb,
                           int a, int b, int c, int d, int tx, int ty)
{
    PutBitContext p;
    uint8_t buf[256];
    int nbits;

    init_put_bits(&p, buf, sizeof(buf));
    
    put_bits(&p, 1, 1); /* a, d present */
    nbits = 1;
    max_nbits(&nbits, a);
    max_nbits(&nbits, d);
    put_bits(&p, 5, nbits); /* nb bits */
    put_bits(&p, nbits, a);
    put_bits(&p, nbits, d);
    
    put_bits(&p, 1, 1); /* b, c present */
    nbits = 1;
    max_nbits(&nbits, c);
    max_nbits(&nbits, b);
    put_bits(&p, 5, nbits); /* nb bits */
    put_bits(&p, nbits, c);
    put_bits(&p, nbits, b);

    nbits = 1;
    max_nbits(&nbits, tx);
    max_nbits(&nbits, ty);
    put_bits(&p, 5, nbits); /* nb bits */
    put_bits(&p, nbits, tx);
    put_bits(&p, nbits, ty);

    flush_put_bits(&p);
    put_buffer(pb, buf, pbBufPtr(&p) - p.buf);
}

/* */
static int swf_write_header(AVFormatContext *s)
{
    SWFContext *swf;
    ByteIOContext *pb = &s->pb;
    AVCodecContext *enc, *audio_enc, *video_enc;
    PutBitContext p;
    uint8_t buf1[256];
    int i, width, height, rate, rate_base;

    swf = av_malloc(sizeof(SWFContext));
    if (!swf)
        return -1;
    s->priv_data = swf;

    swf->ch_id = -1;
    swf->audio_in_pos = 0;
    swf->audio_out_pos = 0;
    swf->audio_size = 0;
    swf->audio_fifo = av_malloc(AUDIO_FIFO_SIZE);
    swf->frame_head = 0;
    swf->frame_tail = 0;
    swf->sound_samples = 0;
    swf->video_samples = 0;
    swf->swf_frame_number = 0;
    swf->video_frame_number = 0;
    swf->skip_samples = 0;

    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 {
            if ( enc->codec_id == CODEC_ID_FLV1 || enc->codec_id == CODEC_ID_MJPEG ) {
                video_enc = enc;
            } else {
                av_log(enc, AV_LOG_ERROR, "SWF only supports FLV1 and MJPEG\n");
                return -1;
            }
        }
    }

    if (!video_enc) {
        /* currenty, cannot work correctly if audio only */
        swf->video_type = 0;
        width = 320;
        height = 200;
        rate = 10;
        rate_base= 1;
    } else {
        swf->video_type = video_enc->codec_id;
        width = video_enc->width;
        height = video_enc->height;
        rate = video_enc->frame_rate;
        rate_base = video_enc->frame_rate_base;
    }

    if (!audio_enc ) {
        swf->audio_type = 0;
        swf->samples_per_frame = ( 44100. * rate_base ) / rate;
    } else {
        swf->audio_type = audio_enc->codec_id;
        swf->samples_per_frame = ( ( audio_enc->sample_rate ) * rate_base ) / rate;
    }

    put_tag(pb, "FWS");
    if ( video_enc && video_enc->codec_id == CODEC_ID_FLV1 ) {
        put_byte(pb, 6); /* version (version 6 and above support FLV1 codec) */
    } else {
        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 * 20, 0, height * 20);
    put_le16(pb, (rate * 256) / rate_base); /* frame rate */
    swf->duration_pos = url_ftell(pb);
    put_le16(pb, (uint16_t)(DUMMY_DURATION * (int64_t)rate / rate_base)); /* frame count */
    
    /* define a shape with the jpeg inside */
    if ( video_enc && video_enc->codec_id == CODEC_ID_FLV1 ) {
    } else if ( video_enc && video_enc->codec_id == CODEC_ID_MJPEG ) {
        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));
        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, pbBufPtr(&p) - p.buf);

        put_swf_end_tag(s);
    }
    
    if (audio_enc && audio_enc->codec_id == CODEC_ID_MP3 ) {
        int v;

        /* start sound */
        put_swf_tag(s, TAG_STREAMHEAD2);

        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 */
            av_free(swf->audio_fifo);
            av_free(swf);
            return -1;
        }
        v |= 0x02; /* 16 bit playback */
        if (audio_enc->channels == 2)
            v |= 0x01; /* stereo playback */
        put_byte(&s->pb, v);
        v |= 0x20; /* mp3 compressed */
        put_byte(&s->pb, v);
        put_le16(&s->pb, swf->samples_per_frame);  /* avg samples per frame */
        put_le16(&s->pb, 0);
        
        put_swf_end_tag(s);
    }

    put_flush_packet(&s->pb);
    return 0;
}

static int swf_write_video(AVFormatContext *s, 
                           AVCodecContext *enc, const uint8_t *buf, int size)
{
    SWFContext *swf = s->priv_data;
    ByteIOContext *pb = &s->pb;
    int c = 0;
    int outSize = 0;
    int outSamples = 0;
    
    /* Flash Player limit */
    if ( swf->swf_frame_number == 16000 ) {
        av_log(enc, AV_LOG_INFO, "warning: Flash Player limit of 16000 frames reached\n");
    }

    /* Store video data in queue */
    if ( enc->codec_type == CODEC_TYPE_VIDEO ) {
        SWFFrame *new_frame = av_malloc(sizeof(SWFFrame));
        new_frame->prev = 0;
        new_frame->next = swf->frame_head;
        new_frame->data = av_malloc(size);