swfenc.c.svn-base

ffmpeg最新源码

/*
 * Flash Compatible Streaming Format muxer
 * Copyright (c) 2000 Fabrice Bellard.
 * Copyright (c) 2003 Tinic Uro.
 *
 * 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 "libavcodec/bitstream.h"
#include "avformat.h"
#include "swf.h"

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

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 = s->priv_data;
    ByteIOContext *pb = s->pb;
    PutBitContext p;
    uint8_t buf1[256];
    int i, width, height, rate, rate_base;
    int version;

    swf->sound_samples = 0;
    swf->swf_frame_number = 0;
    swf->video_frame_number = 0;

    for(i=0;i<s->nb_streams;i++) {
        AVCodecContext *enc = s->streams[i]->codec;
        if (enc->codec_type == CODEC_TYPE_AUDIO) {
            if (enc->codec_id == CODEC_ID_MP3) {
                if (!enc->frame_size) {
                    av_log(s, AV_LOG_ERROR, "audio frame size not set\n");
                    return -1;
                }
                swf->audio_enc = enc;
                av_fifo_init(&swf->audio_fifo, AUDIO_FIFO_SIZE);
            } else {
                av_log(s, AV_LOG_ERROR, "SWF muxer only supports MP3\n");
                return -1;
            }
        } else {
            if (enc->codec_id == CODEC_ID_VP6F ||
                enc->codec_id == CODEC_ID_FLV1 ||
                enc->codec_id == CODEC_ID_MJPEG) {
                swf->video_enc = enc;
            } else {
                av_log(s, AV_LOG_ERROR, "SWF muxer only supports VP6, FLV1 and MJPEG\n");
                return -1;
            }
        }
    }

    if (!swf->video_enc) {
        /* currently, cannot work correctly if audio only */
        width = 320;
        height = 200;
        rate = 10;
        rate_base= 1;
    } else {
        width = swf->video_enc->width;
        height = swf->video_enc->height;
        rate = swf->video_enc->time_base.den;
        rate_base = swf->video_enc->time_base.num;
    }

    if (!swf->audio_enc)
        swf->samples_per_frame = (44100. * rate_base) / rate;
    else
        swf->samples_per_frame = (swf->audio_enc->sample_rate * rate_base) / rate;

    put_tag(pb, "FWS");

    if (!strcmp("avm2", s->oformat->name))
        version = 9;
    else if (swf->video_enc && swf->video_enc->codec_id == CODEC_ID_VP6F)
        version = 8; /* version 8 and above support VP6 codec */
    else if (swf->video_enc && swf->video_enc->codec_id == CODEC_ID_FLV1)
        version = 6; /* version 6 and above support FLV1 codec */
    else
        version = 4; /* version 4 for mpeg audio support */
    put_byte(pb, version);

    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 */

    /* avm2/swf v9 (also v8?) files require a file attribute tag */
    if (version == 9) {
        put_swf_tag(s, TAG_FILEATTRIBUTES);
        put_le32(pb, 1<<3); /* set ActionScript v3/AVM2 flag */
        put_swf_end_tag(s);
    }

    /* define a shape with the jpeg inside */
    if (swf->video_enc && swf->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 */