flvdec.c

ffmpeg移植到symbian的全部源代码

/*
 * FLV demuxer
 * Copyright (c) 2003 The FFmpeg Project.
 *
 * This demuxer will generate a 1 byte extradata for VP6F content.
 * It is composed of:
 *  - upper 4bits: difference between encoded width and visible width
 *  - lower 4bits: difference between encoded height and visible height
 *
 * 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 "avformat.h"
#include "flv.h"

static int flv_probe(AVProbeData *p)
{
    const uint8_t *d;

    d = p->buf;
    if (d[0] == 'F' && d[1] == 'L' && d[2] == 'V' && d[3] < 5 && d[5]==0) {
        return AVPROBE_SCORE_MAX;
    }
    return 0;
}

static void flv_set_audio_codec(AVFormatContext *s, AVStream *astream, int flv_codecid) {
    AVCodecContext *acodec = astream->codec;
    switch(flv_codecid) {
        //no distinction between S16 and S8 PCM codec flags
        case FLV_CODECID_PCM:
            acodec->codec_id = acodec->bits_per_sample == 8 ? CODEC_ID_PCM_S8 :
#ifdef WORDS_BIGENDIAN
                                CODEC_ID_PCM_S16BE;
#else
                                CODEC_ID_PCM_S16LE;
#endif
            break;
        case FLV_CODECID_PCM_LE:
            acodec->codec_id = acodec->bits_per_sample == 8 ? CODEC_ID_PCM_S8 : CODEC_ID_PCM_S16LE; break;
        case FLV_CODECID_AAC  : acodec->codec_id = CODEC_ID_AAC;                                    break;
        case FLV_CODECID_ADPCM: acodec->codec_id = CODEC_ID_ADPCM_SWF;                              break;
        case FLV_CODECID_MP3  : acodec->codec_id = CODEC_ID_MP3      ; astream->need_parsing = AVSTREAM_PARSE_FULL; break;
        case FLV_CODECID_NELLYMOSER_8HZ_MONO:
            acodec->sample_rate = 8000; //in case metadata does not otherwise declare samplerate
        case FLV_CODECID_NELLYMOSER:
            acodec->codec_id = CODEC_ID_NELLYMOSER;
            break;
        default:
            av_log(s, AV_LOG_INFO, "Unsupported audio codec (%x)\n", flv_codecid >> FLV_AUDIO_CODECID_OFFSET);
            acodec->codec_tag = flv_codecid >> FLV_AUDIO_CODECID_OFFSET;
    }
}

static int flv_set_video_codec(AVFormatContext *s, AVStream *vstream, int flv_codecid) {
    AVCodecContext *vcodec = vstream->codec;
    switch(flv_codecid) {
        case FLV_CODECID_H263  : vcodec->codec_id = CODEC_ID_FLV1   ; break;
        case FLV_CODECID_SCREEN: vcodec->codec_id = CODEC_ID_FLASHSV; break;
        case FLV_CODECID_VP6   : vcodec->codec_id = CODEC_ID_VP6F   ;
        case FLV_CODECID_VP6A  :
            if(flv_codecid == FLV_CODECID_VP6A)
                vcodec->codec_id = CODEC_ID_VP6A;
            if(vcodec->extradata_size != 1) {
                vcodec->extradata_size = 1;
                vcodec->extradata = av_malloc(1);
            }
            vcodec->extradata[0] = get_byte(s->pb);
            return 1; // 1 byte body size adjustment for flv_read_packet()
        case FLV_CODECID_H264:
            vcodec->codec_id = CODEC_ID_H264;
            return 3; // not 4, reading packet type will consume one byte
        default:
            av_log(s, AV_LOG_INFO, "Unsupported video codec (%x)\n", flv_codecid);
            vcodec->codec_tag = flv_codecid;
    }

    return 0;
}

static int amf_get_string(ByteIOContext *ioc, char *buffer, int buffsize) {
    int length = get_be16(ioc);
    if(length >= buffsize) {
        url_fskip(ioc, length);
        return -1;
    }

#ifndef __CW32__
    get_buffer(ioc, buffer, length);
#else
    get_buffer(ioc, (unsigned char*)buffer, length);
#endif

    buffer[length] = '\0';

    return length;
}

static int amf_parse_object(AVFormatContext *s, AVStream *astream, AVStream *vstream, const char *key, unsigned int max_pos, int depth) {
    AVCodecContext *acodec, *vcodec;
    ByteIOContext *ioc;
    AMFDataType amf_type;
    char str_val[256];
    double num_val;

    num_val = 0;
    ioc = s->pb;

    amf_type = get_byte(ioc);

    switch(amf_type) {
        case AMF_DATA_TYPE_NUMBER:
            num_val = av_int2dbl(get_be64(ioc)); break;
        case AMF_DATA_TYPE_BOOL:
            num_val = get_byte(ioc); break;
        case AMF_DATA_TYPE_STRING:
            if(amf_get_string(ioc, str_val, sizeof(str_val)) < 0)
                return -1;
            break;
        case AMF_DATA_TYPE_OBJECT: {
            unsigned int keylen;

            while(url_ftell(ioc) < max_pos - 2 && (keylen = get_be16(ioc))) {
                url_fskip(ioc, keylen); //skip key string
                if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
                    return -1; //if we couldn't skip, bomb out.
            }
            if(get_byte(ioc) != AMF_END_OF_OBJECT)
                return -1;
        }
            break;
        case AMF_DATA_TYPE_NULL:
        case AMF_DATA_TYPE_UNDEFINED:
        case AMF_DATA_TYPE_UNSUPPORTED:
            break; //these take up no additional space
        case AMF_DATA_TYPE_MIXEDARRAY:
            url_fskip(ioc, 4); //skip 32-bit max array index
            while(url_ftell(ioc) < max_pos - 2 && amf_get_string(ioc, str_val, sizeof(str_val)) > 0) {
                //this is the only case in which we would want a nested parse to not skip over the object
                if(amf_parse_object(s, astream, vstream, str_val, max_pos, depth + 1) < 0)
                    return -1;
            }
            if(get_byte(ioc) != AMF_END_OF_OBJECT)
                return -1;
            break;
        case AMF_DATA_TYPE_ARRAY: {
            unsigned int arraylen, i;

            arraylen = get_be32(ioc);
            for(i = 0; i < arraylen && url_ftell(ioc) < max_pos - 1; i++) {
                if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
                    return -1; //if we couldn't skip, bomb out.
            }
        }
            break;
        case AMF_DATA_TYPE_DATE:
            url_fskip(ioc, 8 + 2); //timestamp (double) and UTC offset (int16)
            break;
        default: //unsupported type, we couldn't skip
            return -1;
    }

    if(depth == 1 && key) { //only look for metadata values when we are not nested and key != NULL
        acodec = astream ? astream->codec : NULL;
        vcodec = vstream ? vstream->codec : NULL;

        if(amf_type == AMF_DATA_TYPE_BOOL) {
            if(!strcmp(key, "stereo") && acodec) acodec->channels = num_val > 0 ? 2 : 1;
        } else if(amf_type == AMF_DATA_TYPE_NUMBER) {
            if(!strcmp(key, "duration")) s->duration = num_val * AV_TIME_BASE;
//            else if(!strcmp(key, "width")  && vcodec && num_val > 0) vcodec->width  = num_val;
//            else if(!strcmp(key, "height") && vcodec && num_val > 0) vcodec->height = num_val;
            else if(!strcmp(key, "audiocodecid") && acodec && 0 <= (int)num_val)
                flv_set_audio_codec(s, astream, (int)num_val << FLV_AUDIO_CODECID_OFFSET);
            else if(!strcmp(key, "videocodecid") && vcodec && 0 <= (int)num_val)
                flv_set_video_codec(s, vstream, (int)num_val);
            else if(!strcmp(key, "audiosamplesize") && acodec && 0 < (int)num_val) {
                acodec->bits_per_sample = num_val;
                //we may have to rewrite a previously read codecid because FLV only marks PCM endianness.
                if(num_val == 8 && (acodec->codec_id == CODEC_ID_PCM_S16BE || acodec->codec_id == CODEC_ID_PCM_S16LE))
                    acodec->codec_id = CODEC_ID_PCM_S8;
            }
            else if(!strcmp(key, "audiosamplerate") && acodec && num_val >= 0) {
                //some tools, like FLVTool2, write consistently approximate metadata sample rates
                if (!acodec->sample_rate) {
                    switch((int)num_val) {
                        case 44000: acodec->sample_rate = 44100  ; break;
                        case 22000: acodec->sample_rate = 22050  ; break;
                        case 11000: acodec->sample_rate = 11025  ; break;
                        case 5000 : acodec->sample_rate = 5512   ; break;
                        default   : acodec->sample_rate = num_val;
                    }
                }
            }
        }
    }

    return 0;
}

static int flv_read_metabody(AVFormatContext *s, unsigned int next_pos) {
    AMFDataType type;
    AVStream *stream, *astream, *vstream;
    ByteIOContext *ioc;
    int i, keylen;
    char buffer[11]; //only needs to hold the string "onMetaData". Anything longer is something we don't want.

    astream = NULL;
    vstream = NULL;