root/libavformat/swfdec.c

DEFINITIONS

1. get_swf_tag
2. swf_probe
3. zlib_refill
4. swf_read_header
5. create_new_audio_stream
6. swf_read_packet
7. swf_read_close

/*
 * 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 "libavutil/avassert.h"
#include "libavutil/channel_layout.h"
#include "libavutil/imgutils.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(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;

    init_get_bits8(&gb, p->buf + 3, p->buf_size - 3);

    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_MAX;
}

#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 < 0)
        return AVERROR(EINVAL);
    if (ret == Z_STREAM_END)
        return AVERROR_EOF;

    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");
            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->codec->channels       = 2;
        ast->codec->channel_layout = AV_CH_LAYOUT_STEREO;
    } else {
        ast->codec->channels       = 1;
        ast->codec->channel_layout = AV_CH_LAYOUT_MONO;
    }
    ast->codec->codec_type = AVMEDIA_TYPE_AUDIO;
    ast->codec->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->codec->codec_id == AV_CODEC_ID_PCM_S16LE)
        ast->codec->codec_id = AV_CODEC_ID_PCM_U8;
    ast->codec->sample_rate = 44100 >> (3 - sample_rate_code);
    avpriv_set_pts_info(ast, 64, 1, ast->codec->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->codec->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->codec->codec_type = AVMEDIA_TYPE_VIDEO;
            vst->codec->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->codec->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->codec->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->codec->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;

            av_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->codec->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->codec->codec_type = AVMEDIA_TYPE_VIDEO;
                vst->codec->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->codec->width && !st->codec->height) {
                st->codec->width  = width;
                st->codec->height = height;
            } else {
                ff_add_param_change(pkt, 0, 0, 0, width, height);
            }
            pkt->pos = pos;
            pkt->stream_index = st->index;

            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->codec->pix_fmt != AV_PIX_FMT_NONE && st->codec->pix_fmt != pix_fmt) {
                av_log(s, AV_LOG_ERROR, "pixel format change unsupported\n");
                res = AVERROR_PATCHWELCOME;
                goto bitmap_end;
            }
            st->codec->pix_fmt = pix_fmt;

            if (linesize * height > pkt->size) {
                res = AVERROR_INVALIDDATA;
                goto bitmap_end;
            }
            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->codec->codec_type == AVMEDIA_TYPE_AUDIO && st->id == -1) {
                    if (st->codec->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->codec->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->codec->codec_type = AVMEDIA_TYPE_VIDEO;
                vst->codec->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) {
                av_free_packet(pkt);
                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) {
                    av_free_packet(pkt);
                    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, "Cliping 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);
    av_freep(&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
};