asf.c

F:图像处理资料264264书籍ffmpeg-0.4.9-pre1VideoStream.rar 一个视频解压缩源代码

/*
 * ASF compatible decoder.
 * Copyright (c) 2000, 2001 Fabrice Bellard.
 *
 * 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"
#include "avi.h"
#include "mpegaudio.h"
#include "asf.h"

#undef NDEBUG
#include <assert.h>

#define FRAME_HEADER_SIZE 17
// Fix Me! FRAME_HEADER_SIZE may be different. 

static const GUID index_guid = {
    0x33000890, 0xe5b1, 0x11cf, { 0x89, 0xf4, 0x00, 0xa0, 0xc9, 0x03, 0x49, 0xcb },
};

/**********************************/
/* decoding */

//#define DEBUG

#ifdef DEBUG
#define PRINT_IF_GUID(g,cmp) \
if (!memcmp(g, &cmp, sizeof(GUID))) \
    printf("(GUID: %s) ", #cmp)

static void print_guid(const GUID *g)
{
    int i;
    PRINT_IF_GUID(g, asf_header);
    else PRINT_IF_GUID(g, file_header);
    else PRINT_IF_GUID(g, stream_header);
    else PRINT_IF_GUID(g, audio_stream);
    else PRINT_IF_GUID(g, audio_conceal_none);
    else PRINT_IF_GUID(g, video_stream);
    else PRINT_IF_GUID(g, video_conceal_none);
    else PRINT_IF_GUID(g, comment_header);
    else PRINT_IF_GUID(g, codec_comment_header);
    else PRINT_IF_GUID(g, codec_comment1_header);
    else PRINT_IF_GUID(g, data_header);
    else PRINT_IF_GUID(g, index_guid);
    else PRINT_IF_GUID(g, head1_guid);
    else PRINT_IF_GUID(g, head2_guid);
    else PRINT_IF_GUID(g, my_guid);
    else
        printf("(GUID: unknown) ");
    printf("0x%08x, 0x%04x, 0x%04x, {", g->v1, g->v2, g->v3);
    for(i=0;i<8;i++)
        printf(" 0x%02x,", g->v4[i]);
    printf("}\n");
}
#undef PRINT_IF_GUID(g,cmp)
#endif

static void get_guid(ByteIOContext *s, GUID *g)
{
    int i;

    g->v1 = get_le32(s);
    g->v2 = get_le16(s);
    g->v3 = get_le16(s);
    for(i=0;i<8;i++)
        g->v4[i] = get_byte(s);
}

#if 0
static void get_str16(ByteIOContext *pb, char *buf, int buf_size)
{
    int len, c;
    char *q;

    len = get_le16(pb);
    q = buf;
    while (len > 0) {
        c = get_le16(pb);
        if ((q - buf) < buf_size - 1)
            *q++ = c;
        len--;
    }
    *q = '\0';
}
#endif

static void get_str16_nolen(ByteIOContext *pb, int len, char *buf, int buf_size)
{
    int c;
    char *q;

    q = buf;
    while (len > 0) {
        c = get_le16(pb);
        if ((q - buf) < buf_size - 1)
            *q++ = c;
        len-=2;
    }
    *q = '\0';
}

static int asf_probe(AVProbeData *pd)
{
    GUID g;
    const unsigned char *p;
    int i;

    /* check file header */
    if (pd->buf_size <= 32)
        return 0;
    p = pd->buf;
    g.v1 = p[0] | (p[1] << 8) | (p[2] << 16) | (p[3] << 24);
    p += 4;
    g.v2 = p[0] | (p[1] << 8);
    p += 2;
    g.v3 = p[0] | (p[1] << 8);
    p += 2;
    for(i=0;i<8;i++)
        g.v4[i] = *p++;

    if (!memcmp(&g, &asf_header, sizeof(GUID)))
        return AVPROBE_SCORE_MAX;
    else
        return 0;
}

static int asf_read_header(AVFormatContext *s, AVFormatParameters *ap)
{
    ASFContext *asf = s->priv_data;
    GUID g;
    ByteIOContext *pb = &s->pb;
    AVStream *st;
    ASFStream *asf_st;
    int size, i;
    int64_t gsize;

    get_guid(pb, &g);
    if (memcmp(&g, &asf_header, sizeof(GUID)))
        goto fail;
    get_le64(pb);
    get_le32(pb);
    get_byte(pb);
    get_byte(pb);
    memset(&asf->asfid2avid, -1, sizeof(asf->asfid2avid));
    for(;;) {
        get_guid(pb, &g);
        gsize = get_le64(pb);
#ifdef DEBUG
        printf("%08Lx: ", url_ftell(pb) - 24);
        print_guid(&g);
        printf("  size=0x%Lx\n", gsize);
#endif
        if (gsize < 24)
            goto fail;
        if (!memcmp(&g, &file_header, sizeof(GUID))) {
            get_guid(pb, &asf->hdr.guid);
	    asf->hdr.file_size		= get_le64(pb);
	    asf->hdr.create_time	= get_le64(pb);
	    asf->hdr.packets_count	= get_le64(pb);
	    asf->hdr.play_time		= get_le64(pb);
	    asf->hdr.send_time		= get_le64(pb);
	    asf->hdr.preroll		= get_le32(pb);
	    asf->hdr.ignore		= get_le32(pb);
	    asf->hdr.flags		= get_le32(pb);
	    asf->hdr.min_pktsize	= get_le32(pb);
	    asf->hdr.max_pktsize	= get_le32(pb);
	    asf->hdr.max_bitrate	= get_le32(pb);
	    asf->packet_size = asf->hdr.max_pktsize;
            asf->nb_packets = asf->hdr.packets_count;
        } else if (!memcmp(&g, &stream_header, sizeof(GUID))) {
            int type, total_size, type_specific_size;
            unsigned int tag1;
            int64_t pos1, pos2;

            pos1 = url_ftell(pb);

            st = av_new_stream(s, 0);
            if (!st)
                goto fail;
            av_set_pts_info(st, 32, 1, 1000); /* 32 bit pts in ms */
            asf_st = av_mallocz(sizeof(ASFStream));
            if (!asf_st)
                goto fail;
            st->priv_data = asf_st;
            st->start_time = asf->hdr.preroll / (10000000 / AV_TIME_BASE);
	    st->duration = (asf->hdr.send_time - asf->hdr.preroll) / 
                (10000000 / AV_TIME_BASE);
            get_guid(pb, &g);
            if (!memcmp(&g, &audio_stream, sizeof(GUID))) {
                type = CODEC_TYPE_AUDIO;
            } else if (!memcmp(&g, &video_stream, sizeof(GUID))) {
                type = CODEC_TYPE_VIDEO;
            } else {
                goto fail;
            }
            get_guid(pb, &g);
            total_size = get_le64(pb);
            type_specific_size = get_le32(pb);
            get_le32(pb);
	    st->id = get_le16(pb) & 0x7f; /* stream id */
            // mapping of asf ID to AV stream ID;
            asf->asfid2avid[st->id] = s->nb_streams - 1;

            get_le32(pb);
	    st->codec.codec_type = type;
            /* 1 fps default (XXX: put 0 fps instead) */
            st->codec.frame_rate = 1; 
            st->codec.frame_rate_base = 1;
            if (type == CODEC_TYPE_AUDIO) {
                get_wav_header(pb, &st->codec, type_specific_size);
                st->need_parsing = 1;
		/* We have to init the frame size at some point .... */
		pos2 = url_ftell(pb);
		if (gsize > (pos2 + 8 - pos1 + 24)) {
		    asf_st->ds_span = get_byte(pb);
		    asf_st->ds_packet_size = get_le16(pb);
		    asf_st->ds_chunk_size = get_le16(pb);
		    asf_st->ds_data_size = get_le16(pb);
		    asf_st->ds_silence_data = get_byte(pb);
		}
		//printf("Descrambling: ps:%d cs:%d ds:%d s:%d  sd:%d\n",
		//       asf_st->ds_packet_size, asf_st->ds_chunk_size,
		//       asf_st->ds_data_size, asf_st->ds_span, asf_st->ds_silence_data);
		if (asf_st->ds_span > 1) {
		    if (!asf_st->ds_chunk_size
			|| (asf_st->ds_packet_size/asf_st->ds_chunk_size <= 1))
			asf_st->ds_span = 0; // disable descrambling
		}
                switch (st->codec.codec_id) {
                case CODEC_ID_MP3:
                    st->codec.frame_size = MPA_FRAME_SIZE;
                    break;
                case CODEC_ID_PCM_S16LE:
                case CODEC_ID_PCM_S16BE:
                case CODEC_ID_PCM_U16LE:
                case CODEC_ID_PCM_U16BE:
                case CODEC_ID_PCM_S8:
                case CODEC_ID_PCM_U8:
                case CODEC_ID_PCM_ALAW:
                case CODEC_ID_PCM_MULAW:
                    st->codec.frame_size = 1;
                    break;
                default:
                    /* This is probably wrong, but it prevents a crash later */
                    st->codec.frame_size = 1;
                    break;
                }
            } else {
		get_le32(pb);
                get_le32(pb);
                get_byte(pb);
                size = get_le16(pb); /* size */
                get_le32(pb); /* size */
                st->codec.width = get_le32(pb);
		st->codec.height = get_le32(pb);
                /* not available for asf */
                get_le16(pb); /* panes */
		st->codec.bits_per_sample = get_le16(pb); /* depth */
                tag1 = get_le32(pb);
		url_fskip(pb, 20);
		if (size > 40) {
		    st->codec.extradata_size = size - 40;
		    st->codec.extradata = av_mallocz(st->codec.extradata_size);
		    get_buffer(pb, st->codec.extradata, st->codec.extradata_size);
		}

        /* Extract palette from extradata if bpp <= 8 */
        /* This code assumes that extradata contains only palette */
        /* This is true for all paletted codecs implemented in ffmpeg */
        if (st->codec.extradata_size && (st->codec.bits_per_sample <= 8)) {
            st->codec.palctrl = av_mallocz(sizeof(AVPaletteControl));
#ifdef WORDS_BIGENDIAN
            for (i = 0; i < FFMIN(st->codec.extradata_size, AVPALETTE_SIZE)/4; i++)
                st->codec.palctrl->palette[i] = bswap_32(((uint32_t*)st->codec.extradata)[i]);
#else
            memcpy(st->codec.palctrl->palette, st->codec.extradata,
                   FFMIN(st->codec.extradata_size, AVPALETTE_SIZE));
#endif
            st->codec.palctrl->palette_changed = 1;
        }

                st->codec.codec_tag = tag1;
		st->codec.codec_id = codec_get_id(codec_bmp_tags, tag1);
            }
            pos2 = url_ftell(pb);
            url_fskip(pb, gsize - (pos2 - pos1 + 24));
        } else if (!memcmp(&g, &data_header, sizeof(GUID))) {
            break;
        } else if (!memcmp(&g, &comment_header, sizeof(GUID))) {
            int len1, len2, len3, len4, len5;

            len1 = get_le16(pb);
            len2 = get_le16(pb);
            len3 = get_le16(pb);
            len4 = get_le16(pb);
            len5 = get_le16(pb);
            get_str16_nolen(pb, len1, s->title, sizeof(s->title));
            get_str16_nolen(pb, len2, s->author, sizeof(s->author));
            get_str16_nolen(pb, len3, s->copyright, sizeof(s->copyright));
            get_str16_nolen(pb, len4, s->comment, sizeof(s->comment));
	    url_fskip(pb, len5);
       } else if (!memcmp(&g, &extended_content_header, sizeof(GUID))) {
                int desc_count, i;

                desc_count = get_le16(pb);
                for(i=0;i<desc_count;i++)
                {
                        int name_len,value_type,value_len,value_num = 0;
                        char *name, *value;

                        name_len = get_le16(pb);
                        name = (char *)av_mallocz(name_len);
                        get_str16_nolen(pb, name_len, name, name_len);
                        value_type = get_le16(pb);
                        value_len = get_le16(pb);
                        if ((value_type == 0) || (value_type == 1)) // unicode or byte
                        {
                                value = (char *)av_mallocz(value_len);
                                get_str16_nolen(pb, value_len, value, value_len);
                                if (strcmp(name,"WM/AlbumTitle")==0) { strcpy(s->album, value); }
                                av_free(value);
                        }
                        if ((value_type >= 2) || (value_type <= 5)) // boolean or DWORD or QWORD or WORD
                        {
                                if (value_type==2) value_num = get_le32(pb);
                                if (value_type==3) value_num = get_le32(pb);
                                if (value_type==4) value_num = get_le64(pb);
                                if (value_type==5) value_num = get_le16(pb);
                                if (strcmp(name,"WM/Track")==0) s->track = value_num + 1;
                                if (strcmp(name,"WM/TrackNumber")==0) s->track = value_num;
                        }
                        av_free(name);
                }
#if 0
        } else if (!memcmp(&g, &head1_guid, sizeof(GUID))) {
            int v1, v2;
            get_guid(pb, &g);
            v1 = get_le32(pb);
            v2 = get_le16(pb);
        } else if (!memcmp(&g, &codec_comment_header, sizeof(GUID))) {
            int len, v1, n, num;
            char str[256], *q;
            char tag[16];

            get_guid(pb, &g);
            print_guid(&g);

            n = get_le32(pb);
            for(i=0;i<n;i++) {
                num = get_le16(pb); /* stream number */
                get_str16(pb, str, sizeof(str));
                get_str16(pb, str, sizeof(str));
                len = get_le16(pb);
                q = tag;
                while (len > 0) {
                    v1 = get_byte(pb);
                    if ((q - tag) < sizeof(tag) - 1)
                        *q++ = v1;
                    len--;
                }
                *q = '\0';
            }
#endif
        } else if (url_feof(pb)) {
            goto fail;
        } else {
            url_fseek(pb, gsize - 24, SEEK_CUR);
        }
    }
    get_guid(pb, &g);
    get_le64(pb);
    get_byte(pb);
    get_byte(pb);
    if (url_feof(pb))
        goto fail;
    asf->data_offset = url_ftell(pb);
    asf->packet_size_left = 0;

    return 0;

 fail:
     for(i=0;i<s->nb_streams;i++) {
        AVStream *st = s->streams[i];
	if (st) {
	    av_free(st->priv_data);
            av_free(st->codec.extradata);