libavformat/swfdec.c - third_party/ffmpeg - Git at Google

 /*
  * Flash Compatible Streaming Format demuxer
  * 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 "config.h"

 #if CONFIG_ZLIB
 #include <zlib.h>
 #endif

 #include "libavutil/avassert.h"
 #include "libavutil/channel_layout.h"
 #include "libavutil/imgutils.h"
 #include "libavutil/internal.h"
 #include "libavutil/intreadwrite.h"
 #include "libavcodec/get_bits.h"
 #include "swf.h"

 static const AVCodecTag swf_audio_codec_tags[] = {
     { AV_CODEC_ID_PCM_S16LE,  0x00 },
     { AV_CODEC_ID_ADPCM_SWF,  0x01 },
     { AV_CODEC_ID_MP3,        0x02 },
     { AV_CODEC_ID_PCM_S16LE,  0x03 },
 //  { AV_CODEC_ID_NELLYMOSER, 0x06 },
     { AV_CODEC_ID_NONE,          0 },
 };

 static int get_swf_tag(AVIOContext *pb, int *len_ptr)
 {
     int tag, len;

     if (avio_feof(pb))
         return AVERROR_EOF;

     tag = avio_rl16(pb);
     len = tag & 0x3f;
     tag = tag >> 6;
     if (len == 0x3f) {
         len = avio_rl32(pb);
     }
     *len_ptr = len;
     return tag;
 }


 static int swf_probe(const AVProbeData *p)
 {
     GetBitContext gb;
     int len, xmin, xmax, ymin, ymax;

     if(p->buf_size < 15)
         return 0;

     /* check file header */
     if (   AV_RB24(p->buf) != AV_RB24("CWS")
         && AV_RB24(p->buf) != AV_RB24("FWS"))
         return 0;

     if (   AV_RB24(p->buf) == AV_RB24("CWS")
         && p->buf[3] <= 20)
         return AVPROBE_SCORE_MAX / 4 + 1;

     if (init_get_bits8(&gb, p->buf + 3, p->buf_size - 3) < 0)
         return 0;

     skip_bits(&gb, 40);
     len = get_bits(&gb, 5);
     if (!len)
         return 0;
     xmin = get_bits_long(&gb, len);
     xmax = get_bits_long(&gb, len);
     ymin = get_bits_long(&gb, len);
     ymax = get_bits_long(&gb, len);
     if (xmin || ymin || !xmax || !ymax)
         return 0;

     if (p->buf[3] >= 20 || xmax < 16 || ymax < 16)
         return AVPROBE_SCORE_MAX / 4;

     return AVPROBE_SCORE_EXTENSION + 1;
 }

 #if CONFIG_ZLIB
 static int zlib_refill(void *opaque, uint8_t *buf, int buf_size)
 {
     AVFormatContext *s = opaque;
     SWFContext *swf = s->priv_data;
     z_stream *z = &swf->zstream;
     int ret;

 retry:
     if (!z->avail_in) {
         int n = avio_read(s->pb, swf->zbuf_in, ZBUF_SIZE);
         if (n < 0)
             return n;
         z->next_in  = swf->zbuf_in;
         z->avail_in = n;
     }

     z->next_out  = buf;
     z->avail_out = buf_size;

     ret = inflate(z, Z_NO_FLUSH);
     if (ret == Z_STREAM_END)
         return AVERROR_EOF;
     if (ret != Z_OK)
         return AVERROR(EINVAL);

     if (buf_size - z->avail_out == 0)
         goto retry;

     return buf_size - z->avail_out;
 }
 #endif

 static int swf_read_header(AVFormatContext *s)
 {
     SWFContext *swf = s->priv_data;
     AVIOContext *pb = s->pb;
     int nbits, len, tag;

     tag = avio_rb32(pb) & 0xffffff00;
     avio_rl32(pb);

     if (tag == MKBETAG('C', 'W', 'S', 0)) {
         av_log(s, AV_LOG_INFO, "SWF compressed file detected\n");
 #if CONFIG_ZLIB
         swf->zbuf_in  = av_malloc(ZBUF_SIZE);
         swf->zbuf_out = av_malloc(ZBUF_SIZE);
         swf->zpb = avio_alloc_context(swf->zbuf_out, ZBUF_SIZE, 0, s,
                                       zlib_refill, NULL, NULL);
         if (!swf->zbuf_in || !swf->zbuf_out || !swf->zpb)
             return AVERROR(ENOMEM);
         swf->zpb->seekable = 0;
         if (inflateInit(&swf->zstream) != Z_OK) {
             av_log(s, AV_LOG_ERROR, "Unable to init zlib context\n");
             av_freep(&swf->zbuf_in);
             av_freep(&swf->zbuf_out);
             return AVERROR(EINVAL);
         }
         pb = swf->zpb;
 #else
         av_log(s, AV_LOG_ERROR, "zlib support is required to read SWF compressed files\n");
         return AVERROR(EIO);
 #endif
     } else if (tag != MKBETAG('F', 'W', 'S', 0))
         return AVERROR(EIO);
     /* skip rectangle size */
     nbits = avio_r8(pb) >> 3;
     len = (4 * nbits - 3 + 7) / 8;
     avio_skip(pb, len);
     swf->frame_rate = avio_rl16(pb); /* 8.8 fixed */
     avio_rl16(pb); /* frame count */

     swf->samples_per_frame = 0;
     s->ctx_flags |= AVFMTCTX_NOHEADER;
     return 0;
 }

 static AVStream *create_new_audio_stream(AVFormatContext *s, int id, int info)
 {
     int sample_rate_code, sample_size_code;
     AVStream *ast = avformat_new_stream(s, NULL);
     if (!ast)
         return NULL;
     ast->id = id;
     if (info & 1) {
         ast->codecpar->channels       = 2;
         ast->codecpar->channel_layout = AV_CH_LAYOUT_STEREO;
     } else {
         ast->codecpar->channels       = 1;
         ast->codecpar->channel_layout = AV_CH_LAYOUT_MONO;
     }
     ast->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
     ast->codecpar->codec_id   = ff_codec_get_id(swf_audio_codec_tags, info>>4 & 15);
     ast->need_parsing = AVSTREAM_PARSE_FULL;
     sample_rate_code = info>>2 & 3;
     sample_size_code = info>>1 & 1;
     if (!sample_size_code && ast->codecpar->codec_id == AV_CODEC_ID_PCM_S16LE)
         ast->codecpar->codec_id = AV_CODEC_ID_PCM_U8;
     ast->codecpar->sample_rate = 44100 >> (3 - sample_rate_code);
     avpriv_set_pts_info(ast, 64, 1, ast->codecpar->sample_rate);
     return ast;
 }

 static int swf_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     SWFContext *swf = s->priv_data;
     AVIOContext *pb = s->pb;
     AVStream *vst = NULL, *ast = NULL, *st = 0;
     int tag, len, i, frame, v, res;

 #if CONFIG_ZLIB
     if (swf->zpb)
         pb = swf->zpb;
 #endif

     for(;;) {
         uint64_t pos = avio_tell(pb);
         tag = get_swf_tag(pb, &len);
         if (tag < 0)
             return tag;
         if (len < 0) {
             av_log(s, AV_LOG_ERROR, "invalid tag length: %d\n", len);
             return AVERROR_INVALIDDATA;
         }
         if (tag == TAG_VIDEOSTREAM) {
             int ch_id = avio_rl16(pb);
             len -= 2;

             for (i=0; i<s->nb_streams; i++) {
                 st = s->streams[i];
                 if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO && st->id == ch_id)
                     goto skip;
             }

             avio_rl16(pb);
             avio_rl16(pb);
             avio_rl16(pb);
             avio_r8(pb);
             /* Check for FLV1 */
             vst = avformat_new_stream(s, NULL);
             if (!vst)
                 return AVERROR(ENOMEM);
             vst->id = ch_id;
             vst->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
             vst->codecpar->codec_id = ff_codec_get_id(ff_swf_codec_tags, avio_r8(pb));
             avpriv_set_pts_info(vst, 16, 256, swf->frame_rate);
             len -= 8;
         } else if (tag == TAG_STREAMHEAD || tag == TAG_STREAMHEAD2) {
             /* streaming found */

             for (i=0; i<s->nb_streams; i++) {
                 st = s->streams[i];
                 if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO && st->id == -1)
                     goto skip;
             }

             avio_r8(pb);
             v = avio_r8(pb);
             swf->samples_per_frame = avio_rl16(pb);
             ast = create_new_audio_stream(s, -1, v); /* -1 to avoid clash with video stream ch_id */
             if (!ast)
                 return AVERROR(ENOMEM);
             len -= 4;
         } else if (tag == TAG_DEFINESOUND) {
             /* audio stream */
             int ch_id = avio_rl16(pb);

             for (i=0; i<s->nb_streams; i++) {
                 st = s->streams[i];
                 if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO && st->id == ch_id)
                     goto skip;
             }

             // FIXME: The entire audio stream is stored in a single chunk/tag. Normally,
             // these are smaller audio streams in DEFINESOUND tags, but it's technically
             // possible they could be huge. Break it up into multiple packets if it's big.
             v = avio_r8(pb);
             ast = create_new_audio_stream(s, ch_id, v);
             if (!ast)
                 return AVERROR(ENOMEM);
             ast->duration = avio_rl32(pb); // number of samples
             if (((v>>4) & 15) == 2) { // MP3 sound data record
                 ast->skip_samples = avio_rl16(pb);
                 len -= 2;
             }
             len -= 7;
             if ((res = av_get_packet(pb, pkt, len)) < 0)
                 return res;
             pkt->pos = pos;
             pkt->stream_index = ast->index;
             return pkt->size;
         } else if (tag == TAG_VIDEOFRAME) {
             int ch_id = avio_rl16(pb);
             len -= 2;
             for(i=0; i<s->nb_streams; i++) {
                 st = s->streams[i];
                 if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO && st->id == ch_id) {
                     frame = avio_rl16(pb);
                     len -= 2;
                     if (len <= 0)
                         goto skip;
                     if ((res = av_get_packet(pb, pkt, len)) < 0)
                         return res;
                     pkt->pos = pos;
                     pkt->pts = frame;
                     pkt->stream_index = st->index;
                     return pkt->size;
                 }
             }
         } else if (tag == TAG_DEFINEBITSLOSSLESS || tag == TAG_DEFINEBITSLOSSLESS2) {
 #if CONFIG_ZLIB
             long out_len;
             uint8_t *buf = NULL, *zbuf = NULL, *pal;
             uint32_t colormap[AVPALETTE_COUNT] = {0};
             const int alpha_bmp = tag == TAG_DEFINEBITSLOSSLESS2;
             const int colormapbpp = 3 + alpha_bmp;
             int linesize, colormapsize = 0;

             const int ch_id   = avio_rl16(pb);
             const int bmp_fmt = avio_r8(pb);
             const int width   = avio_rl16(pb);
             const int height  = avio_rl16(pb);
             int pix_fmt;

             len -= 2+1+2+2;

             switch (bmp_fmt) {
             case 3: // PAL-8
                 linesize = width;
                 colormapsize = avio_r8(pb) + 1;
                 len--;
                 break;
             case 4: // RGB15
                 linesize = width * 2;
                 break;
             case 5: // RGB24 (0RGB)
                 linesize = width * 4;
                 break;
             default:
                 av_log(s, AV_LOG_ERROR, "invalid bitmap format %d, skipped\n", bmp_fmt);
                 goto bitmap_end_skip;
             }

             linesize = FFALIGN(linesize, 4);

             if (av_image_check_size(width, height, 0, s) < 0 ||
                 linesize >= INT_MAX / height ||
                 linesize * height >= INT_MAX - colormapsize * colormapbpp) {
                 av_log(s, AV_LOG_ERROR, "invalid frame size %dx%d\n", width, height);
                 goto bitmap_end_skip;
             }

             out_len = colormapsize * colormapbpp + linesize * height;

             ff_dlog(s, "bitmap: ch=%d fmt=%d %dx%d (linesize=%d) len=%d->%ld pal=%d\n",
                     ch_id, bmp_fmt, width, height, linesize, len, out_len, colormapsize);

             zbuf = av_malloc(len);
             buf  = av_malloc(out_len);
             if (!zbuf || !buf) {
                 res = AVERROR(ENOMEM);
                 goto bitmap_end;
             }

             len = avio_read(pb, zbuf, len);
             if (len < 0 || (res = uncompress(buf, &out_len, zbuf, len)) != Z_OK) {
                 av_log(s, AV_LOG_WARNING, "Failed to uncompress one bitmap\n");
                 goto bitmap_end_skip;
             }

             for (i = 0; i < s->nb_streams; i++) {
                 st = s->streams[i];
                 if (st->codecpar->codec_id == AV_CODEC_ID_RAWVIDEO && st->id == -3)
                     break;
             }
             if (i == s->nb_streams) {
                 vst = avformat_new_stream(s, NULL);
                 if (!vst) {
                     res = AVERROR(ENOMEM);
                     goto bitmap_end;
                 }
                 vst->id = -3; /* -3 to avoid clash with video stream and audio stream */
                 vst->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
                 vst->codecpar->codec_id = AV_CODEC_ID_RAWVIDEO;
                 avpriv_set_pts_info(vst, 64, 256, swf->frame_rate);
                 st = vst;
             }

             if ((res = av_new_packet(pkt, out_len - colormapsize * colormapbpp)) < 0)
                 goto bitmap_end;
             if (!st->codecpar->width && !st->codecpar->height) {
                 st->codecpar->width  = width;
                 st->codecpar->height = height;
             } else {
                 ff_add_param_change(pkt, 0, 0, 0, width, height);
             }
             pkt->pos = pos;
             pkt->stream_index = st->index;

             if (linesize * height > pkt->size) {
                 res = AVERROR_INVALIDDATA;
                 goto bitmap_end;
             }

             switch (bmp_fmt) {
             case 3:
                 pix_fmt = AV_PIX_FMT_PAL8;
                 for (i = 0; i < colormapsize; i++)
                     if (alpha_bmp)  colormap[i] = buf[3]<<24 | AV_RB24(buf + 4*i);
                     else            colormap[i] = 0xffU <<24 | AV_RB24(buf + 3*i);
                 pal = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE, AVPALETTE_SIZE);
                 if (!pal) {
                     res = AVERROR(ENOMEM);
                     goto bitmap_end;
                 }
                 memcpy(pal, colormap, AVPALETTE_SIZE);
                 break;
             case 4:
                 pix_fmt = AV_PIX_FMT_RGB555;
                 break;
             case 5:
                 pix_fmt = alpha_bmp ? AV_PIX_FMT_ARGB : AV_PIX_FMT_0RGB;
                 break;
             default:
                 av_assert0(0);
             }
             if (st->codecpar->format != AV_PIX_FMT_NONE && st->codecpar->format != pix_fmt) {
                 av_log(s, AV_LOG_ERROR, "pixel format change unsupported\n");
             } else
                 st->codecpar->format = pix_fmt;

             memcpy(pkt->data, buf + colormapsize*colormapbpp, linesize * height);

             res = pkt->size;

 bitmap_end:
             av_freep(&zbuf);
             av_freep(&buf);
             return res;
 bitmap_end_skip:
             av_freep(&zbuf);
             av_freep(&buf);
 #else
             av_log(s, AV_LOG_ERROR, "this file requires zlib support compiled in\n");
 #endif
         } else if (tag == TAG_STREAMBLOCK) {
             for (i = 0; i < s->nb_streams; i++) {
                 st = s->streams[i];
                 if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO && st->id == -1) {
                     if (st->codecpar->codec_id == AV_CODEC_ID_MP3) {
                         avio_skip(pb, 4);
                         len -= 4;
                         if (len <= 0)
                             goto skip;
                         if ((res = av_get_packet(pb, pkt, len)) < 0)
                             return res;
                     } else { // ADPCM, PCM
                         if (len <= 0)
                             goto skip;
                         if ((res = av_get_packet(pb, pkt, len)) < 0)
                             return res;
                     }
                     pkt->pos          = pos;
                     pkt->stream_index = st->index;
                     return pkt->size;
                 }
             }
         } else if (tag == TAG_JPEG2) {
             for (i=0; i<s->nb_streams; i++) {
                 st = s->streams[i];
                 if (st->codecpar->codec_id == AV_CODEC_ID_MJPEG && st->id == -2)
                     break;
             }
             if (i == s->nb_streams) {
                 vst = avformat_new_stream(s, NULL);
                 if (!vst)
                     return AVERROR(ENOMEM);
                 vst->id = -2; /* -2 to avoid clash with video stream and audio stream */
                 vst->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
                 vst->codecpar->codec_id = AV_CODEC_ID_MJPEG;
                 avpriv_set_pts_info(vst, 64, 256, swf->frame_rate);
                 st = vst;
             }
             avio_rl16(pb); /* BITMAP_ID */
             len -= 2;
             if (len < 4)
                 goto skip;
             if ((res = av_new_packet(pkt, len)) < 0)
                 return res;
             if (avio_read(pb, pkt->data, 4) != 4) {
                 return AVERROR_INVALIDDATA;
             }
             if (AV_RB32(pkt->data) == 0xffd8ffd9 ||
                 AV_RB32(pkt->data) == 0xffd9ffd8) {
                 /* old SWF files containing SOI/EOI as data start */
                 /* files created by swink have reversed tag */
                 pkt->size -= 4;
                 memset(pkt->data+pkt->size, 0, 4);
                 res = avio_read(pb, pkt->data, pkt->size);
             } else {
                 res = avio_read(pb, pkt->data + 4, pkt->size - 4);
                 if (res >= 0)
                     res += 4;
             }
             if (res != pkt->size) {
                 if (res < 0) {
                     return res;
                 }
                 av_shrink_packet(pkt, res);
             }

             pkt->pos = pos;
             pkt->stream_index = st->index;
             return pkt->size;
         } else {
             av_log(s, AV_LOG_DEBUG, "Unknown tag: %d\n", tag);
         }
     skip:
         if(len<0)
             av_log(s, AV_LOG_WARNING, "Clipping len %d\n", len);
         len = FFMAX(0, len);
         avio_skip(pb, len);
     }
 }

 #if CONFIG_ZLIB
 static av_cold int swf_read_close(AVFormatContext *avctx)
 {
     SWFContext *s = avctx->priv_data;
     inflateEnd(&s->zstream);
     av_freep(&s->zbuf_in);
     av_freep(&s->zbuf_out);
     avio_context_free(&s->zpb);
     return 0;
 }
 #endif

 AVInputFormat ff_swf_demuxer = {
     .name           = "swf",
     .long_name      = NULL_IF_CONFIG_SMALL("SWF (ShockWave Flash)"),
     .priv_data_size = sizeof(SWFContext),
     .read_probe     = swf_probe,
     .read_header    = swf_read_header,
     .read_packet    = swf_read_packet,
 #if CONFIG_ZLIB
     .read_close     = swf_read_close,
 #endif
 };
	/*
	* Flash Compatible Streaming Format demuxer
	* 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 "config.h"

	#if CONFIG_ZLIB
	#include <zlib.h>
	#endif

	#include "libavutil/avassert.h"
	#include "libavutil/channel_layout.h"
	#include "libavutil/imgutils.h"
	#include "libavutil/internal.h"
	#include "libavutil/intreadwrite.h"
	#include "libavcodec/get_bits.h"
	#include "swf.h"

	static const AVCodecTag swf_audio_codec_tags[] = {
	{ AV_CODEC_ID_PCM_S16LE, 0x00 },
	{ AV_CODEC_ID_ADPCM_SWF, 0x01 },
	{ AV_CODEC_ID_MP3, 0x02 },
	{ AV_CODEC_ID_PCM_S16LE, 0x03 },
	// { AV_CODEC_ID_NELLYMOSER, 0x06 },
	{ AV_CODEC_ID_NONE, 0 },
	};

	static int get_swf_tag(AVIOContext pb, int len_ptr)
	{
	int tag, len;

	if (avio_feof(pb))
	return AVERROR_EOF;

	tag = avio_rl16(pb);
	len = tag & 0x3f;
	tag = tag >> 6;
	if (len == 0x3f) {
	len = avio_rl32(pb);
	}
	*len_ptr = len;
	return tag;
	}


	static int swf_probe(const AVProbeData *p)
	{
	GetBitContext gb;
	int len, xmin, xmax, ymin, ymax;

	if(p->buf_size < 15)
	return 0;

	/* check file header */
	if ( AV_RB24(p->buf) != AV_RB24("CWS")
	&& AV_RB24(p->buf) != AV_RB24("FWS"))
	return 0;

	if ( AV_RB24(p->buf) == AV_RB24("CWS")
	&& p->buf[3] <= 20)
	return AVPROBE_SCORE_MAX / 4 + 1;

	if (init_get_bits8(&gb, p->buf + 3, p->buf_size - 3) < 0)
	return 0;

	skip_bits(&gb, 40);
	len = get_bits(&gb, 5);
	if (!len)
	return 0;
	xmin = get_bits_long(&gb, len);
	xmax = get_bits_long(&gb, len);
	ymin = get_bits_long(&gb, len);
	ymax = get_bits_long(&gb, len);
	if (xmin \|\| ymin \|\| !xmax \|\| !ymax)
	return 0;

	if (p->buf[3] >= 20 \|\| xmax < 16 \|\| ymax < 16)
	return AVPROBE_SCORE_MAX / 4;

	return AVPROBE_SCORE_EXTENSION + 1;
	}

	#if CONFIG_ZLIB
	static int zlib_refill(void opaque, uint8_t buf, int buf_size)
	{
	AVFormatContext *s = opaque;
	SWFContext *swf = s->priv_data;
	z_stream *z = &swf->zstream;
	int ret;

	retry:
	if (!z->avail_in) {
	int n = avio_read(s->pb, swf->zbuf_in, ZBUF_SIZE);
	if (n < 0)
	return n;
	z->next_in = swf->zbuf_in;
	z->avail_in = n;
	}

	z->next_out = buf;
	z->avail_out = buf_size;

	ret = inflate(z, Z_NO_FLUSH);
	if (ret == Z_STREAM_END)
	return AVERROR_EOF;
	if (ret != Z_OK)
	return AVERROR(EINVAL);

	if (buf_size - z->avail_out == 0)
	goto retry;

	return buf_size - z->avail_out;
	}
	#endif

	static int swf_read_header(AVFormatContext *s)
	{
	SWFContext *swf = s->priv_data;
	AVIOContext *pb = s->pb;
	int nbits, len, tag;

	tag = avio_rb32(pb) & 0xffffff00;
	avio_rl32(pb);

	if (tag == MKBETAG('C', 'W', 'S', 0)) {
	av_log(s, AV_LOG_INFO, "SWF compressed file detected\n");
	#if CONFIG_ZLIB
	swf->zbuf_in = av_malloc(ZBUF_SIZE);
	swf->zbuf_out = av_malloc(ZBUF_SIZE);
	swf->zpb = avio_alloc_context(swf->zbuf_out, ZBUF_SIZE, 0, s,
	zlib_refill, NULL, NULL);
	if (!swf->zbuf_in \|\| !swf->zbuf_out \|\| !swf->zpb)
	return AVERROR(ENOMEM);
	swf->zpb->seekable = 0;
	if (inflateInit(&swf->zstream) != Z_OK) {
	av_log(s, AV_LOG_ERROR, "Unable to init zlib context\n");
	av_freep(&swf->zbuf_in);
	av_freep(&swf->zbuf_out);
	return AVERROR(EINVAL);
	}
	pb = swf->zpb;
	#else
	av_log(s, AV_LOG_ERROR, "zlib support is required to read SWF compressed files\n");
	return AVERROR(EIO);
	#endif
	} else if (tag != MKBETAG('F', 'W', 'S', 0))
	return AVERROR(EIO);
	/* skip rectangle size */
	nbits = avio_r8(pb) >> 3;
	len = (4 * nbits - 3 + 7) / 8;
	avio_skip(pb, len);
	swf->frame_rate = avio_rl16(pb); /* 8.8 fixed */
	avio_rl16(pb); /* frame count */

	swf->samples_per_frame = 0;
	s->ctx_flags \|= AVFMTCTX_NOHEADER;
	return 0;
	}

	static AVStream create_new_audio_stream(AVFormatContext s, int id, int info)
	{
	int sample_rate_code, sample_size_code;
	AVStream *ast = avformat_new_stream(s, NULL);
	if (!ast)
	return NULL;
	ast->id = id;
	if (info & 1) {
	ast->codecpar->channels = 2;
	ast->codecpar->channel_layout = AV_CH_LAYOUT_STEREO;
	} else {
	ast->codecpar->channels = 1;
	ast->codecpar->channel_layout = AV_CH_LAYOUT_MONO;
	}
	ast->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
	ast->codecpar->codec_id = ff_codec_get_id(swf_audio_codec_tags, info>>4 & 15);
	ast->need_parsing = AVSTREAM_PARSE_FULL;
	sample_rate_code = info>>2 & 3;
	sample_size_code = info>>1 & 1;
	if (!sample_size_code && ast->codecpar->codec_id == AV_CODEC_ID_PCM_S16LE)
	ast->codecpar->codec_id = AV_CODEC_ID_PCM_U8;
	ast->codecpar->sample_rate = 44100 >> (3 - sample_rate_code);
	avpriv_set_pts_info(ast, 64, 1, ast->codecpar->sample_rate);
	return ast;
	}

	static int swf_read_packet(AVFormatContext s, AVPacket pkt)
	{
	SWFContext *swf = s->priv_data;
	AVIOContext *pb = s->pb;
	AVStream vst = NULL, ast = NULL, *st = 0;
	int tag, len, i, frame, v, res;

	#if CONFIG_ZLIB
	if (swf->zpb)
	pb = swf->zpb;
	#endif

	for(;;) {
	uint64_t pos = avio_tell(pb);
	tag = get_swf_tag(pb, &len);
	if (tag < 0)
	return tag;
	if (len < 0) {
	av_log(s, AV_LOG_ERROR, "invalid tag length: %d\n", len);
	return AVERROR_INVALIDDATA;
	}
	if (tag == TAG_VIDEOSTREAM) {
	int ch_id = avio_rl16(pb);
	len -= 2;

	for (i=0; i<s->nb_streams; i++) {
	st = s->streams[i];
	if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO && st->id == ch_id)
	goto skip;
	}

	avio_rl16(pb);
	avio_rl16(pb);
	avio_rl16(pb);
	avio_r8(pb);
	/* Check for FLV1 */
	vst = avformat_new_stream(s, NULL);
	if (!vst)
	return AVERROR(ENOMEM);
	vst->id = ch_id;
	vst->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
	vst->codecpar->codec_id = ff_codec_get_id(ff_swf_codec_tags, avio_r8(pb));
	avpriv_set_pts_info(vst, 16, 256, swf->frame_rate);
	len -= 8;
	} else if (tag == TAG_STREAMHEAD \|\| tag == TAG_STREAMHEAD2) {
	/* streaming found */

	for (i=0; i<s->nb_streams; i++) {
	st = s->streams[i];
	if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO && st->id == -1)
	goto skip;
	}

	avio_r8(pb);
	v = avio_r8(pb);
	swf->samples_per_frame = avio_rl16(pb);
	ast = create_new_audio_stream(s, -1, v); /* -1 to avoid clash with video stream ch_id */
	if (!ast)
	return AVERROR(ENOMEM);
	len -= 4;
	} else if (tag == TAG_DEFINESOUND) {
	/* audio stream */
	int ch_id = avio_rl16(pb);

	for (i=0; i<s->nb_streams; i++) {
	st = s->streams[i];
	if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO && st->id == ch_id)
	goto skip;
	}

	// FIXME: The entire audio stream is stored in a single chunk/tag. Normally,
	// these are smaller audio streams in DEFINESOUND tags, but it's technically
	// possible they could be huge. Break it up into multiple packets if it's big.
	v = avio_r8(pb);
	ast = create_new_audio_stream(s, ch_id, v);
	if (!ast)
	return AVERROR(ENOMEM);
	ast->duration = avio_rl32(pb); // number of samples
	if (((v>>4) & 15) == 2) { // MP3 sound data record
	ast->skip_samples = avio_rl16(pb);
	len -= 2;
	}
	len -= 7;
	if ((res = av_get_packet(pb, pkt, len)) < 0)
	return res;
	pkt->pos = pos;
	pkt->stream_index = ast->index;
	return pkt->size;
	} else if (tag == TAG_VIDEOFRAME) {
	int ch_id = avio_rl16(pb);
	len -= 2;
	for(i=0; i<s->nb_streams; i++) {
	st = s->streams[i];
	if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO && st->id == ch_id) {
	frame = avio_rl16(pb);
	len -= 2;
	if (len <= 0)
	goto skip;
	if ((res = av_get_packet(pb, pkt, len)) < 0)
	return res;
	pkt->pos = pos;
	pkt->pts = frame;
	pkt->stream_index = st->index;
	return pkt->size;
	}
	}
	} else if (tag == TAG_DEFINEBITSLOSSLESS \|\| tag == TAG_DEFINEBITSLOSSLESS2) {
	#if CONFIG_ZLIB
	long out_len;
	uint8_t buf = NULL, zbuf = NULL, *pal;
	uint32_t colormap[AVPALETTE_COUNT] = {0};
	const int alpha_bmp = tag == TAG_DEFINEBITSLOSSLESS2;
	const int colormapbpp = 3 + alpha_bmp;
	int linesize, colormapsize = 0;

	const int ch_id = avio_rl16(pb);
	const int bmp_fmt = avio_r8(pb);
	const int width = avio_rl16(pb);
	const int height = avio_rl16(pb);
	int pix_fmt;

	len -= 2+1+2+2;

	switch (bmp_fmt) {
	case 3: // PAL-8
	linesize = width;
	colormapsize = avio_r8(pb) + 1;
	len--;
	break;
	case 4: // RGB15
	linesize = width * 2;
	break;
	case 5: // RGB24 (0RGB)
	linesize = width * 4;
	break;
	default:
	av_log(s, AV_LOG_ERROR, "invalid bitmap format %d, skipped\n", bmp_fmt);
	goto bitmap_end_skip;
	}

	linesize = FFALIGN(linesize, 4);

	if (av_image_check_size(width, height, 0, s) < 0 \|\|
	linesize >= INT_MAX / height \|\|
	linesize * height >= INT_MAX - colormapsize * colormapbpp) {
	av_log(s, AV_LOG_ERROR, "invalid frame size %dx%d\n", width, height);
	goto bitmap_end_skip;
	}

	out_len = colormapsize * colormapbpp + linesize * height;

	ff_dlog(s, "bitmap: ch=%d fmt=%d %dx%d (linesize=%d) len=%d->%ld pal=%d\n",
	ch_id, bmp_fmt, width, height, linesize, len, out_len, colormapsize);

	zbuf = av_malloc(len);
	buf = av_malloc(out_len);
	if (!zbuf \|\| !buf) {
	res = AVERROR(ENOMEM);
	goto bitmap_end;
	}

	len = avio_read(pb, zbuf, len);
	if (len < 0 \|\| (res = uncompress(buf, &out_len, zbuf, len)) != Z_OK) {
	av_log(s, AV_LOG_WARNING, "Failed to uncompress one bitmap\n");
	goto bitmap_end_skip;
	}

	for (i = 0; i < s->nb_streams; i++) {
	st = s->streams[i];
	if (st->codecpar->codec_id == AV_CODEC_ID_RAWVIDEO && st->id == -3)
	break;
	}
	if (i == s->nb_streams) {
	vst = avformat_new_stream(s, NULL);
	if (!vst) {
	res = AVERROR(ENOMEM);
	goto bitmap_end;
	}
	vst->id = -3; /* -3 to avoid clash with video stream and audio stream */
	vst->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
	vst->codecpar->codec_id = AV_CODEC_ID_RAWVIDEO;
	avpriv_set_pts_info(vst, 64, 256, swf->frame_rate);
	st = vst;
	}

	if ((res = av_new_packet(pkt, out_len - colormapsize * colormapbpp)) < 0)
	goto bitmap_end;
	if (!st->codecpar->width && !st->codecpar->height) {
	st->codecpar->width = width;
	st->codecpar->height = height;
	} else {
	ff_add_param_change(pkt, 0, 0, 0, width, height);
	}
	pkt->pos = pos;
	pkt->stream_index = st->index;

	if (linesize * height > pkt->size) {
	res = AVERROR_INVALIDDATA;
	goto bitmap_end;
	}

	switch (bmp_fmt) {
	case 3:
	pix_fmt = AV_PIX_FMT_PAL8;
	for (i = 0; i < colormapsize; i++)
	if (alpha_bmp) colormap[i] = buf[3]<<24 \| AV_RB24(buf + 4*i);
	else colormap[i] = 0xffU <<24 \| AV_RB24(buf + 3*i);
	pal = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE, AVPALETTE_SIZE);
	if (!pal) {
	res = AVERROR(ENOMEM);
	goto bitmap_end;
	}
	memcpy(pal, colormap, AVPALETTE_SIZE);
	break;
	case 4:
	pix_fmt = AV_PIX_FMT_RGB555;
	break;
	case 5:
	pix_fmt = alpha_bmp ? AV_PIX_FMT_ARGB : AV_PIX_FMT_0RGB;
	break;
	default:
	av_assert0(0);
	}
	if (st->codecpar->format != AV_PIX_FMT_NONE && st->codecpar->format != pix_fmt) {
	av_log(s, AV_LOG_ERROR, "pixel format change unsupported\n");
	} else
	st->codecpar->format = pix_fmt;

	memcpy(pkt->data, buf + colormapsizecolormapbpp, linesize height);

	res = pkt->size;

	bitmap_end:
	av_freep(&zbuf);
	av_freep(&buf);
	return res;
	bitmap_end_skip:
	av_freep(&zbuf);
	av_freep(&buf);
	#else
	av_log(s, AV_LOG_ERROR, "this file requires zlib support compiled in\n");
	#endif
	} else if (tag == TAG_STREAMBLOCK) {
	for (i = 0; i < s->nb_streams; i++) {
	st = s->streams[i];
	if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO && st->id == -1) {
	if (st->codecpar->codec_id == AV_CODEC_ID_MP3) {
	avio_skip(pb, 4);
	len -= 4;
	if (len <= 0)
	goto skip;
	if ((res = av_get_packet(pb, pkt, len)) < 0)
	return res;
	} else { // ADPCM, PCM
	if (len <= 0)
	goto skip;
	if ((res = av_get_packet(pb, pkt, len)) < 0)
	return res;
	}
	pkt->pos = pos;
	pkt->stream_index = st->index;
	return pkt->size;
	}
	}
	} else if (tag == TAG_JPEG2) {
	for (i=0; i<s->nb_streams; i++) {
	st = s->streams[i];
	if (st->codecpar->codec_id == AV_CODEC_ID_MJPEG && st->id == -2)
	break;
	}
	if (i == s->nb_streams) {
	vst = avformat_new_stream(s, NULL);
	if (!vst)
	return AVERROR(ENOMEM);
	vst->id = -2; /* -2 to avoid clash with video stream and audio stream */
	vst->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
	vst->codecpar->codec_id = AV_CODEC_ID_MJPEG;
	avpriv_set_pts_info(vst, 64, 256, swf->frame_rate);
	st = vst;
	}
	avio_rl16(pb); /* BITMAP_ID */
	len -= 2;
	if (len < 4)
	goto skip;
	if ((res = av_new_packet(pkt, len)) < 0)
	return res;
	if (avio_read(pb, pkt->data, 4) != 4) {
	return AVERROR_INVALIDDATA;
	}
	if (AV_RB32(pkt->data) == 0xffd8ffd9 \|\|
	AV_RB32(pkt->data) == 0xffd9ffd8) {
	/* old SWF files containing SOI/EOI as data start */
	/* files created by swink have reversed tag */
	pkt->size -= 4;
	memset(pkt->data+pkt->size, 0, 4);
	res = avio_read(pb, pkt->data, pkt->size);
	} else {
	res = avio_read(pb, pkt->data + 4, pkt->size - 4);
	if (res >= 0)
	res += 4;
	}
	if (res != pkt->size) {
	if (res < 0) {
	return res;
	}
	av_shrink_packet(pkt, res);
	}

	pkt->pos = pos;
	pkt->stream_index = st->index;
	return pkt->size;
	} else {
	av_log(s, AV_LOG_DEBUG, "Unknown tag: %d\n", tag);
	}
	skip:
	if(len<0)
	av_log(s, AV_LOG_WARNING, "Clipping len %d\n", len);
	len = FFMAX(0, len);
	avio_skip(pb, len);
	}
	}

	#if CONFIG_ZLIB
	static av_cold int swf_read_close(AVFormatContext *avctx)
	{
	SWFContext *s = avctx->priv_data;
	inflateEnd(&s->zstream);
	av_freep(&s->zbuf_in);
	av_freep(&s->zbuf_out);
	avio_context_free(&s->zpb);
	return 0;
	}
	#endif

	AVInputFormat ff_swf_demuxer = {
	.name = "swf",
	.long_name = NULL_IF_CONFIG_SMALL("SWF (ShockWave Flash)"),
	.priv_data_size = sizeof(SWFContext),
	.read_probe = swf_probe,
	.read_header = swf_read_header,
	.read_packet = swf_read_packet,
	#if CONFIG_ZLIB
	.read_close = swf_read_close,
	#endif
	};