libavformat/swfenc.c - nest-android-app/ffmpeg - Git at Google

 /*
  * 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/put_bits.h"
 #include "libavutil/avassert.h"
 #include "avformat.h"
 #include "swf.h"

 static void put_swf_tag(AVFormatContext *s, int tag)
 {
     SWFContext *swf = s->priv_data;
     AVIOContext *pb = s->pb;

     swf->tag_pos = avio_tell(pb);
     swf->tag = tag;
     /* reserve some room for the tag */
     if (tag & TAG_LONG) {
         avio_wl16(pb, 0);
         avio_wl32(pb, 0);
     } else {
         avio_wl16(pb, 0);
     }
 }

 static void put_swf_end_tag(AVFormatContext *s)
 {
     SWFContext *swf = s->priv_data;
     AVIOContext *pb = s->pb;
     int64_t pos;
     int tag_len, tag;

     pos = avio_tell(pb);
     tag_len = pos - swf->tag_pos - 2;
     tag = swf->tag;
     avio_seek(pb, swf->tag_pos, SEEK_SET);
     if (tag & TAG_LONG) {
         tag &= ~TAG_LONG;
         avio_wl16(pb, (tag << 6) | 0x3f);
         avio_wl32(pb, tag_len - 4);
     } else {
         av_assert0(tag_len < 0x3f);
         avio_wl16(pb, (tag << 6) | tag_len);
     }
     avio_seek(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(AVIOContext *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);
     avio_write(pb, buf, put_bits_ptr(&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(AVIOContext *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);
     avio_write(pb, buf, put_bits_ptr(&p) - p.buf);
 }

 static int swf_write_header(AVFormatContext *s)
 {
     SWFContext *swf = s->priv_data;
     AVIOContext *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 == AVMEDIA_TYPE_AUDIO) {
             if (swf->audio_enc) {
                 av_log(s, AV_LOG_ERROR, "SWF muxer only supports 1 audio stream\n");
                 return AVERROR_INVALIDDATA;
             }
             if (enc->codec_id == AV_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;
                 swf->audio_fifo= av_fifo_alloc(AUDIO_FIFO_SIZE);
                 if (!swf->audio_fifo)
                     return AVERROR(ENOMEM);
             } else {
                 av_log(s, AV_LOG_ERROR, "SWF muxer only supports MP3\n");
                 return -1;
             }
         } else {
             if (swf->video_enc) {
                 av_log(s, AV_LOG_ERROR, "SWF muxer only supports 1 video stream\n");
                 return AVERROR_INVALIDDATA;
             }
             if (enc->codec_id == AV_CODEC_ID_VP6F ||
                 enc->codec_id == AV_CODEC_ID_FLV1 ||
                 enc->codec_id == AV_CODEC_ID_MJPEG) {
                 swf->video_st  = s->streams[i];
                 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;
         // TODO: should be avg_frame_rate
         rate = swf->video_st->time_base.den;
         rate_base = swf->video_st->time_base.num;
     }

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

     avio_write(pb, "FWS", 3);

     if (!strcmp("avm2", s->oformat->name))
         version = 9;
     else if (swf->video_enc && swf->video_enc->codec_id == AV_CODEC_ID_VP6F)
         version = 8; /* version 8 and above support VP6 codec */
     else if (swf->video_enc && swf->video_enc->codec_id == AV_CODEC_ID_FLV1)
         version = 6; /* version 6 and above support FLV1 codec */
     else
         version = 4; /* version 4 for mpeg audio support */
     avio_w8(pb, version);

     avio_wl32(pb, DUMMY_FILE_SIZE); /* dummy size
                                       (will be patched if not streamed) */

     put_swf_rect(pb, 0, width * 20, 0, height * 20);
     if ((rate * 256LL) / rate_base >= (1<<16)) {
         av_log(s, AV_LOG_ERROR, "Invalid (too large) frame rate %d/%d\n", rate, rate_base);
         return AVERROR(EINVAL);
     }
     avio_wl16(pb, (rate * 256) / rate_base); /* frame rate */
     swf->duration_pos = avio_tell(pb);
     avio_wl16(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);
         avio_wl32(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 == AV_CODEC_ID_MJPEG) {
         put_swf_tag(s, TAG_DEFINESHAPE);

         avio_wl16(pb, SHAPE_ID); /* ID of shape */
         /* bounding rectangle */
         put_swf_rect(pb, 0, width, 0, height);
         /* style info */
         avio_w8(pb, 1); /* one fill style */
         avio_w8(pb, 0x41); /* clipped bitmap fill */
         avio_wl16(pb, BITMAP_ID); /* bitmap ID */
         /* position of the bitmap */
         put_swf_matrix(pb, 1 << FRAC_BITS, 0,
                        0,  1 << FRAC_BITS, 0, 0);
         avio_w8(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);
         avio_write(pb, buf1, put_bits_ptr(&p) - p.buf);

         put_swf_end_tag(s);
     }

     if (swf->audio_enc && swf->audio_enc->codec_id == AV_CODEC_ID_MP3) {
         int v = 0;

         /* start sound */
         put_swf_tag(s, TAG_STREAMHEAD2);
         switch(swf->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_log(s, AV_LOG_ERROR, "swf does not support that sample rate, choose from (44100, 22050, 11025).\n");
             return -1;
         }
         v |= 0x02; /* 16 bit playback */
         if (swf->audio_enc->channels == 2)
             v |= 0x01; /* stereo playback */
         avio_w8(s->pb, v);
         v |= 0x20; /* mp3 compressed */
         avio_w8(s->pb, v);
         avio_wl16(s->pb, swf->samples_per_frame);  /* avg samples per frame */
         avio_wl16(s->pb, 0);

         put_swf_end_tag(s);
     }

     avio_flush(s->pb);
     return 0;
 }

 static int swf_write_video(AVFormatContext *s,
                            AVCodecContext *enc, const uint8_t *buf, int size)
 {
     SWFContext *swf = s->priv_data;
     AVIOContext *pb = s->pb;

     /* Flash Player limit */
     if (swf->swf_frame_number == 16000)
         av_log(enc, AV_LOG_INFO, "warning: Flash Player limit of 16000 frames reached\n");

     if (enc->codec_id == AV_CODEC_ID_VP6F ||
         enc->codec_id == AV_CODEC_ID_FLV1) {
         if (swf->video_frame_number == 0) {
             /* create a new video object */
             put_swf_tag(s, TAG_VIDEOSTREAM);
             avio_wl16(pb, VIDEO_ID);
             swf->vframes_pos = avio_tell(pb);
             avio_wl16(pb, 15000); /* hard flash player limit */
             avio_wl16(pb, enc->width);
             avio_wl16(pb, enc->height);
             avio_w8(pb, 0);
             avio_w8(pb,ff_codec_get_tag(ff_swf_codec_tags, enc->codec_id));
             put_swf_end_tag(s);

             /* place the video object for the first time */
             put_swf_tag(s, TAG_PLACEOBJECT2);
             avio_w8(pb, 0x36);
             avio_wl16(pb, 1);
             avio_wl16(pb, VIDEO_ID);
             put_swf_matrix(pb, 1 << FRAC_BITS, 0, 0, 1 << FRAC_BITS, 0, 0);
             avio_wl16(pb, swf->video_frame_number);
             avio_write(pb, "video", 5);
             avio_w8(pb, 0x00);
             put_swf_end_tag(s);
         } else {
             /* mark the character for update */
             put_swf_tag(s, TAG_PLACEOBJECT2);
             avio_w8(pb, 0x11);
             avio_wl16(pb, 1);
             avio_wl16(pb, swf->video_frame_number);
             put_swf_end_tag(s);
         }

         /* set video frame data */
         put_swf_tag(s, TAG_VIDEOFRAME | TAG_LONG);
         avio_wl16(pb, VIDEO_ID);
         avio_wl16(pb, swf->video_frame_number++);
         avio_write(pb, buf, size);
         put_swf_end_tag(s);
     } else if (enc->codec_id == AV_CODEC_ID_MJPEG) {
         if (swf->swf_frame_number > 0) {
             /* remove the shape */
             put_swf_tag(s, TAG_REMOVEOBJECT);
             avio_wl16(pb, SHAPE_ID); /* shape ID */
             avio_wl16(pb, 1); /* depth */
             put_swf_end_tag(s);

             /* free the bitmap */
             put_swf_tag(s, TAG_FREECHARACTER);
             avio_wl16(pb, BITMAP_ID);
             put_swf_end_tag(s);
         }

         put_swf_tag(s, TAG_JPEG2 | TAG_LONG);

         avio_wl16(pb, BITMAP_ID); /* ID of the image */

         /* a dummy jpeg header seems to be required */
         avio_wb32(pb, 0xffd8ffd9);
         /* write the jpeg image */
         avio_write(pb, buf, size);

         put_swf_end_tag(s);

         /* draw the shape */

         put_swf_tag(s, TAG_PLACEOBJECT);
         avio_wl16(pb, SHAPE_ID); /* shape ID */
         avio_wl16(pb, 1); /* depth */
         put_swf_matrix(pb, 20 << FRAC_BITS, 0, 0, 20 << FRAC_BITS, 0, 0);
         put_swf_end_tag(s);
     }

     swf->swf_frame_number++;

     /* streaming sound always should be placed just before showframe tags */
     if (swf->audio_enc && av_fifo_size(swf->audio_fifo)) {
         int frame_size = av_fifo_size(swf->audio_fifo);
         put_swf_tag(s, TAG_STREAMBLOCK | TAG_LONG);
         avio_wl16(pb, swf->sound_samples);
         avio_wl16(pb, 0); // seek samples
         av_fifo_generic_read(swf->audio_fifo, pb, frame_size, (void*)avio_write);
         put_swf_end_tag(s);

         /* update FIFO */
         swf->sound_samples = 0;
     }

     /* output the frame */
     put_swf_tag(s, TAG_SHOWFRAME);
     put_swf_end_tag(s);

     return 0;
 }

 static int swf_write_audio(AVFormatContext *s,
                            AVCodecContext *enc, uint8_t *buf, int size)
 {
     SWFContext *swf = s->priv_data;

     /* Flash Player limit */
     if (swf->swf_frame_number == 16000)
         av_log(enc, AV_LOG_INFO, "warning: Flash Player limit of 16000 frames reached\n");

     if (av_fifo_size(swf->audio_fifo) + size > AUDIO_FIFO_SIZE) {
         av_log(s, AV_LOG_ERROR, "audio fifo too small to mux audio essence\n");
         return -1;
     }

     av_fifo_generic_write(swf->audio_fifo, buf, size, NULL);
     swf->sound_samples += enc->frame_size;

     /* if audio only stream make sure we add swf frames */
     if (!swf->video_enc)
         swf_write_video(s, enc, 0, 0);

     return 0;
 }

 static int swf_write_packet(AVFormatContext *s, AVPacket *pkt)
 {
     AVCodecContext *codec = s->streams[pkt->stream_index]->codec;
     if (codec->codec_type == AVMEDIA_TYPE_AUDIO)
         return swf_write_audio(s, codec, pkt->data, pkt->size);
     else
         return swf_write_video(s, codec, pkt->data, pkt->size);
 }

 static int swf_write_trailer(AVFormatContext *s)
 {
     SWFContext *swf = s->priv_data;
     AVIOContext *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 == AVMEDIA_TYPE_VIDEO)
             video_enc = enc;
         else {
             av_fifo_freep(&swf->audio_fifo);
         }
     }

     put_swf_tag(s, TAG_END);
     put_swf_end_tag(s);

     /* patch file size and number of frames if not streamed */
     if (s->pb->seekable && video_enc) {
         file_size = avio_tell(pb);
         avio_seek(pb, 4, SEEK_SET);
         avio_wl32(pb, file_size);
         avio_seek(pb, swf->duration_pos, SEEK_SET);
         avio_wl16(pb, swf->video_frame_number);
         if (swf->vframes_pos) {
         avio_seek(pb, swf->vframes_pos, SEEK_SET);
         avio_wl16(pb, swf->video_frame_number);
         }
         avio_seek(pb, file_size, SEEK_SET);
     }
     return 0;
 }

 #if CONFIG_SWF_MUXER
 AVOutputFormat ff_swf_muxer = {
     .name              = "swf",
     .long_name         = NULL_IF_CONFIG_SMALL("SWF (ShockWave Flash)"),
     .mime_type         = "application/x-shockwave-flash",
     .extensions        = "swf",
     .priv_data_size    = sizeof(SWFContext),
     .audio_codec       = AV_CODEC_ID_MP3,
     .video_codec       = AV_CODEC_ID_FLV1,
     .write_header      = swf_write_header,
     .write_packet      = swf_write_packet,
     .write_trailer     = swf_write_trailer,
     .flags             = AVFMT_TS_NONSTRICT,
 };
 #endif
 #if CONFIG_AVM2_MUXER
 AVOutputFormat ff_avm2_muxer = {
     .name              = "avm2",
     .long_name         = NULL_IF_CONFIG_SMALL("SWF (ShockWave Flash) (AVM2)"),
     .mime_type         = "application/x-shockwave-flash",
     .priv_data_size    = sizeof(SWFContext),
     .audio_codec       = AV_CODEC_ID_MP3,
     .video_codec       = AV_CODEC_ID_FLV1,
     .write_header      = swf_write_header,
     .write_packet      = swf_write_packet,
     .write_trailer     = swf_write_trailer,
     .flags             = AVFMT_TS_NONSTRICT,
 };
 #endif
	/*
	* 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/put_bits.h"
	#include "libavutil/avassert.h"
	#include "avformat.h"
	#include "swf.h"

	static void put_swf_tag(AVFormatContext *s, int tag)
	{
	SWFContext *swf = s->priv_data;
	AVIOContext *pb = s->pb;

	swf->tag_pos = avio_tell(pb);
	swf->tag = tag;
	/* reserve some room for the tag */
	if (tag & TAG_LONG) {
	avio_wl16(pb, 0);
	avio_wl32(pb, 0);
	} else {
	avio_wl16(pb, 0);
	}
	}

	static void put_swf_end_tag(AVFormatContext *s)
	{
	SWFContext *swf = s->priv_data;
	AVIOContext *pb = s->pb;
	int64_t pos;
	int tag_len, tag;

	pos = avio_tell(pb);
	tag_len = pos - swf->tag_pos - 2;
	tag = swf->tag;
	avio_seek(pb, swf->tag_pos, SEEK_SET);
	if (tag & TAG_LONG) {
	tag &= ~TAG_LONG;
	avio_wl16(pb, (tag << 6) \| 0x3f);
	avio_wl32(pb, tag_len - 4);
	} else {
	av_assert0(tag_len < 0x3f);
	avio_wl16(pb, (tag << 6) \| tag_len);
	}
	avio_seek(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(AVIOContext *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);
	avio_write(pb, buf, put_bits_ptr(&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(AVIOContext *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);
	avio_write(pb, buf, put_bits_ptr(&p) - p.buf);
	}

	static int swf_write_header(AVFormatContext *s)
	{
	SWFContext *swf = s->priv_data;
	AVIOContext *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 == AVMEDIA_TYPE_AUDIO) {
	if (swf->audio_enc) {
	av_log(s, AV_LOG_ERROR, "SWF muxer only supports 1 audio stream\n");
	return AVERROR_INVALIDDATA;
	}
	if (enc->codec_id == AV_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;
	swf->audio_fifo= av_fifo_alloc(AUDIO_FIFO_SIZE);
	if (!swf->audio_fifo)
	return AVERROR(ENOMEM);
	} else {
	av_log(s, AV_LOG_ERROR, "SWF muxer only supports MP3\n");
	return -1;
	}
	} else {
	if (swf->video_enc) {
	av_log(s, AV_LOG_ERROR, "SWF muxer only supports 1 video stream\n");
	return AVERROR_INVALIDDATA;
	}
	if (enc->codec_id == AV_CODEC_ID_VP6F \|\|
	enc->codec_id == AV_CODEC_ID_FLV1 \|\|
	enc->codec_id == AV_CODEC_ID_MJPEG) {
	swf->video_st = s->streams[i];
	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;
	// TODO: should be avg_frame_rate
	rate = swf->video_st->time_base.den;
	rate_base = swf->video_st->time_base.num;
	}

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

	avio_write(pb, "FWS", 3);

	if (!strcmp("avm2", s->oformat->name))
	version = 9;
	else if (swf->video_enc && swf->video_enc->codec_id == AV_CODEC_ID_VP6F)
	version = 8; /* version 8 and above support VP6 codec */
	else if (swf->video_enc && swf->video_enc->codec_id == AV_CODEC_ID_FLV1)
	version = 6; /* version 6 and above support FLV1 codec */
	else
	version = 4; /* version 4 for mpeg audio support */
	avio_w8(pb, version);

	avio_wl32(pb, DUMMY_FILE_SIZE); /* dummy size
	(will be patched if not streamed) */

	put_swf_rect(pb, 0, width * 20, 0, height * 20);
	if ((rate * 256LL) / rate_base >= (1<<16)) {
	av_log(s, AV_LOG_ERROR, "Invalid (too large) frame rate %d/%d\n", rate, rate_base);
	return AVERROR(EINVAL);
	}
	avio_wl16(pb, (rate * 256) / rate_base); /* frame rate */
	swf->duration_pos = avio_tell(pb);
	avio_wl16(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);
	avio_wl32(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 == AV_CODEC_ID_MJPEG) {
	put_swf_tag(s, TAG_DEFINESHAPE);

	avio_wl16(pb, SHAPE_ID); /* ID of shape */
	/* bounding rectangle */
	put_swf_rect(pb, 0, width, 0, height);
	/* style info */
	avio_w8(pb, 1); /* one fill style */
	avio_w8(pb, 0x41); /* clipped bitmap fill */
	avio_wl16(pb, BITMAP_ID); /* bitmap ID */
	/* position of the bitmap */
	put_swf_matrix(pb, 1 << FRAC_BITS, 0,
	0, 1 << FRAC_BITS, 0, 0);
	avio_w8(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);
	avio_write(pb, buf1, put_bits_ptr(&p) - p.buf);

	put_swf_end_tag(s);
	}

	if (swf->audio_enc && swf->audio_enc->codec_id == AV_CODEC_ID_MP3) {
	int v = 0;

	/* start sound */
	put_swf_tag(s, TAG_STREAMHEAD2);
	switch(swf->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_log(s, AV_LOG_ERROR, "swf does not support that sample rate, choose from (44100, 22050, 11025).\n");
	return -1;
	}
	v \|= 0x02; /* 16 bit playback */
	if (swf->audio_enc->channels == 2)
	v \|= 0x01; /* stereo playback */
	avio_w8(s->pb, v);
	v \|= 0x20; /* mp3 compressed */
	avio_w8(s->pb, v);
	avio_wl16(s->pb, swf->samples_per_frame); /* avg samples per frame */
	avio_wl16(s->pb, 0);

	put_swf_end_tag(s);
	}

	avio_flush(s->pb);
	return 0;
	}

	static int swf_write_video(AVFormatContext *s,
	AVCodecContext enc, const uint8_t buf, int size)
	{
	SWFContext *swf = s->priv_data;
	AVIOContext *pb = s->pb;

	/* Flash Player limit */
	if (swf->swf_frame_number == 16000)
	av_log(enc, AV_LOG_INFO, "warning: Flash Player limit of 16000 frames reached\n");

	if (enc->codec_id == AV_CODEC_ID_VP6F \|\|
	enc->codec_id == AV_CODEC_ID_FLV1) {
	if (swf->video_frame_number == 0) {
	/* create a new video object */
	put_swf_tag(s, TAG_VIDEOSTREAM);
	avio_wl16(pb, VIDEO_ID);
	swf->vframes_pos = avio_tell(pb);
	avio_wl16(pb, 15000); /* hard flash player limit */
	avio_wl16(pb, enc->width);
	avio_wl16(pb, enc->height);
	avio_w8(pb, 0);
	avio_w8(pb,ff_codec_get_tag(ff_swf_codec_tags, enc->codec_id));
	put_swf_end_tag(s);

	/* place the video object for the first time */
	put_swf_tag(s, TAG_PLACEOBJECT2);
	avio_w8(pb, 0x36);
	avio_wl16(pb, 1);
	avio_wl16(pb, VIDEO_ID);
	put_swf_matrix(pb, 1 << FRAC_BITS, 0, 0, 1 << FRAC_BITS, 0, 0);
	avio_wl16(pb, swf->video_frame_number);
	avio_write(pb, "video", 5);
	avio_w8(pb, 0x00);
	put_swf_end_tag(s);
	} else {
	/* mark the character for update */
	put_swf_tag(s, TAG_PLACEOBJECT2);
	avio_w8(pb, 0x11);
	avio_wl16(pb, 1);
	avio_wl16(pb, swf->video_frame_number);
	put_swf_end_tag(s);
	}

	/* set video frame data */
	put_swf_tag(s, TAG_VIDEOFRAME \| TAG_LONG);
	avio_wl16(pb, VIDEO_ID);
	avio_wl16(pb, swf->video_frame_number++);
	avio_write(pb, buf, size);
	put_swf_end_tag(s);
	} else if (enc->codec_id == AV_CODEC_ID_MJPEG) {
	if (swf->swf_frame_number > 0) {
	/* remove the shape */
	put_swf_tag(s, TAG_REMOVEOBJECT);
	avio_wl16(pb, SHAPE_ID); /* shape ID */
	avio_wl16(pb, 1); /* depth */
	put_swf_end_tag(s);

	/* free the bitmap */
	put_swf_tag(s, TAG_FREECHARACTER);
	avio_wl16(pb, BITMAP_ID);
	put_swf_end_tag(s);
	}

	put_swf_tag(s, TAG_JPEG2 \| TAG_LONG);

	avio_wl16(pb, BITMAP_ID); /* ID of the image */

	/* a dummy jpeg header seems to be required */
	avio_wb32(pb, 0xffd8ffd9);
	/* write the jpeg image */
	avio_write(pb, buf, size);

	put_swf_end_tag(s);

	/* draw the shape */

	put_swf_tag(s, TAG_PLACEOBJECT);
	avio_wl16(pb, SHAPE_ID); /* shape ID */
	avio_wl16(pb, 1); /* depth */
	put_swf_matrix(pb, 20 << FRAC_BITS, 0, 0, 20 << FRAC_BITS, 0, 0);
	put_swf_end_tag(s);
	}

	swf->swf_frame_number++;

	/* streaming sound always should be placed just before showframe tags */
	if (swf->audio_enc && av_fifo_size(swf->audio_fifo)) {
	int frame_size = av_fifo_size(swf->audio_fifo);
	put_swf_tag(s, TAG_STREAMBLOCK \| TAG_LONG);
	avio_wl16(pb, swf->sound_samples);
	avio_wl16(pb, 0); // seek samples
	av_fifo_generic_read(swf->audio_fifo, pb, frame_size, (void*)avio_write);
	put_swf_end_tag(s);

	/* update FIFO */
	swf->sound_samples = 0;
	}

	/* output the frame */
	put_swf_tag(s, TAG_SHOWFRAME);
	put_swf_end_tag(s);

	return 0;
	}

	static int swf_write_audio(AVFormatContext *s,
	AVCodecContext enc, uint8_t buf, int size)
	{
	SWFContext *swf = s->priv_data;

	/* Flash Player limit */
	if (swf->swf_frame_number == 16000)
	av_log(enc, AV_LOG_INFO, "warning: Flash Player limit of 16000 frames reached\n");

	if (av_fifo_size(swf->audio_fifo) + size > AUDIO_FIFO_SIZE) {
	av_log(s, AV_LOG_ERROR, "audio fifo too small to mux audio essence\n");
	return -1;
	}

	av_fifo_generic_write(swf->audio_fifo, buf, size, NULL);
	swf->sound_samples += enc->frame_size;

	/* if audio only stream make sure we add swf frames */
	if (!swf->video_enc)
	swf_write_video(s, enc, 0, 0);

	return 0;
	}

	static int swf_write_packet(AVFormatContext s, AVPacket pkt)
	{
	AVCodecContext *codec = s->streams[pkt->stream_index]->codec;
	if (codec->codec_type == AVMEDIA_TYPE_AUDIO)
	return swf_write_audio(s, codec, pkt->data, pkt->size);
	else
	return swf_write_video(s, codec, pkt->data, pkt->size);
	}

	static int swf_write_trailer(AVFormatContext *s)
	{
	SWFContext *swf = s->priv_data;
	AVIOContext *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 == AVMEDIA_TYPE_VIDEO)
	video_enc = enc;
	else {
	av_fifo_freep(&swf->audio_fifo);
	}
	}

	put_swf_tag(s, TAG_END);
	put_swf_end_tag(s);

	/* patch file size and number of frames if not streamed */
	if (s->pb->seekable && video_enc) {
	file_size = avio_tell(pb);
	avio_seek(pb, 4, SEEK_SET);
	avio_wl32(pb, file_size);
	avio_seek(pb, swf->duration_pos, SEEK_SET);
	avio_wl16(pb, swf->video_frame_number);
	if (swf->vframes_pos) {
	avio_seek(pb, swf->vframes_pos, SEEK_SET);
	avio_wl16(pb, swf->video_frame_number);
	}
	avio_seek(pb, file_size, SEEK_SET);
	}
	return 0;
	}

	#if CONFIG_SWF_MUXER
	AVOutputFormat ff_swf_muxer = {
	.name = "swf",
	.long_name = NULL_IF_CONFIG_SMALL("SWF (ShockWave Flash)"),
	.mime_type = "application/x-shockwave-flash",
	.extensions = "swf",
	.priv_data_size = sizeof(SWFContext),
	.audio_codec = AV_CODEC_ID_MP3,
	.video_codec = AV_CODEC_ID_FLV1,
	.write_header = swf_write_header,
	.write_packet = swf_write_packet,
	.write_trailer = swf_write_trailer,
	.flags = AVFMT_TS_NONSTRICT,
	};
	#endif
	#if CONFIG_AVM2_MUXER
	AVOutputFormat ff_avm2_muxer = {
	.name = "avm2",
	.long_name = NULL_IF_CONFIG_SMALL("SWF (ShockWave Flash) (AVM2)"),
	.mime_type = "application/x-shockwave-flash",
	.priv_data_size = sizeof(SWFContext),
	.audio_codec = AV_CODEC_ID_MP3,
	.video_codec = AV_CODEC_ID_FLV1,
	.write_header = swf_write_header,
	.write_packet = swf_write_packet,
	.write_trailer = swf_write_trailer,
	.flags = AVFMT_TS_NONSTRICT,
	};
	#endif