mpv/libmpdemux/demux_nsv.c

/*
 * Nullsoft Streaming Video demuxer
 * for MPlayer
 * by Reza Jelveh <reza.jelveh@tuhh.de>
 * seeking and PCM audio not yet supported
 * PCM needs extra audio chunk "miniheader" parsing
 * Based on A'rpis G2 work
 * Licence: GPL
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#include "config.h"
#include "mp_msg.h"
#include "help_mp.h"
#include "stream.h"
#include "demuxer.h"
#include "stheader.h"

typedef struct {
    float   v_pts;  
    int video_pack_no;
    unsigned int a_format;
    unsigned int v_format;
    unsigned char fps;            
} nsv_priv_t;

/**
 * Seeking still to be implemented
 */
void demux_seek_nsv ( demuxer_t *demuxer, float rel_seek_secs, int flags )
{
// seeking is not yet implemented
}


int demux_nsv_fill_buffer ( demuxer_t *demuxer )
{  
    unsigned char hdr[17];
    // for the extra data
    unsigned char aux[6];
    int i_aux = 0;
    // videolen = audio chunk length, audiolen = video chunk length
    int videolen,audiolen; 

    sh_video_t *sh_video = demuxer->video->sh;
    sh_audio_t *sh_audio = demuxer->audio->sh;

    nsv_priv_t * priv = demuxer->priv;

    // if the audio/video chunk has no new header the first 2 bytes will be discarded 0xBEEF 
    // or rather 0xEF 0xBE
    stream_read(demuxer->stream,hdr,7);
    if(stream_eof(demuxer->stream)) return 0;
    // sometimes instead of 0xBEEF as described for the next audio/video chunk we get
    // a whole new header
    
    mp_dbg(MSGT_DEMUX,MSGL_DBG2,"demux_nsv: %08X %08X\n",hdr[0]<<8|hdr[1],stream_tell(demuxer->stream));
    switch(hdr[0]<<8|hdr[1]) {
        case 0x4E53:
            if(hdr[2]==0x56 && hdr[3]==0x73){
                // NSVs
                // get the header since there is no more metaheader after the first one 
                // there is no more need to skip that
                stream_read(demuxer->stream,hdr+7,17-7);
                stream_read(demuxer->stream,hdr,7);
            }
            break;
        
        case 0xEFBE:
            break;

        default:
            mp_dbg(MSGT_DEMUX,MSGL_WARN,"demux_nsv: sync lost\n");
            break;
    }

    if (sh_video)
    sh_video->pts = priv->v_pts =demuxer->video->pts=  priv->video_pack_no *
         (float)sh_video->frametime;
    else
        priv->v_pts = priv->video_pack_no;

    demuxer->filepos=stream_tell(demuxer->stream);


    mp_dbg(MSGT_DEMUX,MSGL_DBG2,"demux_nsv: %08X: %02X %02X | %02X %02X %02X | %02X %02X  \n",
    (int)demuxer->filepos, hdr[0],hdr[1],hdr[2],hdr[3],hdr[4],hdr[5],hdr[6]);

    // read video:
    videolen=(hdr[2]>>4)|(hdr[3]<<4)|(hdr[4]<<0xC);
    //check if we got extra data like subtitles here
    if( (hdr[2]&0x0f) != 0x0 ) {
        stream_read( demuxer->stream, aux, 6); 

        i_aux = aux[0]|aux[1]<<8;
        // We skip this extra data 
        stream_skip( demuxer->stream, i_aux );
        i_aux+=6;
        videolen -= i_aux;
    }
    

    // we need to return an empty packet when the 
    // video frame is empty otherwise the stream will fasten up 
    if(sh_video) {
        if( (hdr[2]&0x0f) != 0x0 )
            ds_read_packet(demuxer->video,demuxer->stream,videolen,priv->v_pts,demuxer->filepos-i_aux,0);
        else 
            ds_read_packet(demuxer->video,demuxer->stream,videolen,priv->v_pts,demuxer->filepos,0);
    }
    else
        stream_skip(demuxer->stream,videolen);

    // read audio:
    audiolen=(hdr[5])|(hdr[6]<<8);
    // we need to return an empty packet when the 
    // audio frame is empty otherwise the stream will fasten up 
    if(sh_audio) {
        ds_read_packet(demuxer->audio,demuxer->stream,audiolen,priv->v_pts,demuxer->filepos+videolen,0);
    }
    else
        stream_skip(demuxer->stream,audiolen);

    ++priv->video_pack_no;

    return 1;
    
}


demuxer_t* demux_open_nsv ( demuxer_t* demuxer )
{
    // last 2 bytes 17 and 18 are unknown but right after that comes the length
    unsigned char hdr[17];
    int videolen,audiolen;
    unsigned char buf[10];
    sh_video_t *sh_video = NULL;
    sh_audio_t *sh_audio = NULL;
    
    
    nsv_priv_t * priv = malloc(sizeof(nsv_priv_t));
    demuxer->priv=priv;
    priv->video_pack_no=0;

      /* disable seeking yet to be fixed*/
    demuxer->seekable = 0;
        
    stream_read(demuxer->stream,hdr,4);
    if(stream_eof(demuxer->stream)) return 0;
    
    /*** if we detected the file to be nsv and there was neither eof nor a header
    **** that means that its most likely a shoutcast stream so we will need to seek
    **** to the first occurance of the NSVs header                      ****/
    if(!(hdr[0]==0x4E && hdr[1]==0x53 && hdr[2]==0x56)){
        // todo: replace this with a decent string search algo 
        while(1){
            stream_read(demuxer->stream,hdr,1);
            if(stream_eof(demuxer->stream)) 
                return 0;
            if(hdr[0]!=0x4E)
                continue;
                
            stream_read(demuxer->stream,hdr+1,1);
            
            if(stream_eof(demuxer->stream)) 
                return 0;
            if(hdr[1]!=0x53)
                continue;
                
            stream_read(demuxer->stream,hdr+2,1);
            
            if(stream_eof(demuxer->stream)) 
                return 0;
            if(hdr[2]!=0x56)
                continue;
                
            stream_read(demuxer->stream,hdr+3,1);
            
            if(stream_eof(demuxer->stream)) 
                return 0;
            if(hdr[3]!=0x73)
                continue;
            
            break;
        }
    }
    if(hdr[0]==0x4E && hdr[1]==0x53 && hdr[2]==0x56){
        // NSV header!
        if(hdr[3]==0x73){
            // NSVs
            stream_read(demuxer->stream,hdr+4,17-4);            
        }

        if(hdr[3]==0x66){
            // NSVf
            int len=stream_read_dword_le(demuxer->stream);
            // TODO: parse out metadata!!!!
            stream_skip(demuxer->stream,len-8);
                
            // NSVs
            stream_read(demuxer->stream,hdr,17);        
        }

        // dummy debug message
        mp_msg(MSGT_DEMUX,MSGL_V,"demux_nsv: Header: %.12s\n",hdr);

        //   bytes 8-11   audio codec fourcc
        // PCM fourcc needs extra parsing for every audio chunk, yet to implement
        if((demuxer->audio->id != -2) && strncmp(hdr+8,"NONE", 4)){//&&strncmp(hdr+8,"VLB ", 4)){
            sh_audio = new_sh_audio ( demuxer, 0 );
            demuxer->audio->sh = sh_audio;
            sh_audio->format=mmioFOURCC(hdr[8],hdr[9],hdr[10],hdr[11]);
            sh_audio->ds = demuxer->audio;
            priv->a_format=mmioFOURCC(hdr[8],hdr[9],hdr[10],hdr[11]);
        }

        // store hdr fps 
        priv->fps=hdr[16];
            
        if ((demuxer->video->id != -2) && strncmp(hdr+4,"NONE", 4)) {
            /* Create a new video stream header */
            sh_video = new_sh_video ( demuxer, 0 );

            /* Make sure the demuxer knows about the new video stream header
             * (even though new_sh_video() ought to take care of it)
             */
            demuxer->video->sh = sh_video;

            /* Make sure that the video demuxer stream header knows about its
             * parent video demuxer stream (this is getting wacky), or else
             * video_read_properties() will choke
             */
            sh_video->ds = demuxer->video;
        
            //   bytes 4-7  video codec fourcc
            priv->v_format = sh_video->format=mmioFOURCC(hdr[4],hdr[5],hdr[6],hdr[7]);
        
            // new video stream! parse header
            sh_video->disp_w=hdr[12]|(hdr[13]<<8);
            sh_video->disp_h=hdr[14]|(hdr[15]<<8);
            sh_video->bih=(BITMAPINFOHEADER*)calloc(1,sizeof(BITMAPINFOHEADER));
            sh_video->bih->biSize=sizeof(BITMAPINFOHEADER);
            sh_video->bih->biPlanes=1; 
            sh_video->bih->biBitCount=24;
            sh_video->bih->biWidth=hdr[12]|(hdr[13]<<8);
            sh_video->bih->biHeight=hdr[14]|(hdr[15]<<8);
            memcpy(&sh_video->bih->biCompression,hdr+4,4);
            sh_video->bih->biSizeImage=sh_video->bih->biWidth*sh_video->bih->biHeight*3;

            // here we search for the correct keyframe 
            // vp6 keyframe is when the 2nd byte of the vp6 header is
            // 0x36 for VP61 and 0x46 for VP62
            if((priv->v_format==mmioFOURCC('V','P','6','1')) ||
               (priv->v_format==mmioFOURCC('V','P','6','2')) ||
               (priv->v_format==mmioFOURCC('V','P','3','1'))) {
                stream_read(demuxer->stream,buf,10);
                if (((((priv->v_format>>16) & 0xff) == '6') && ((buf[8]&0x0e)!=0x06)) ||
                    ((((priv->v_format>>16) & 0xff) == '3') && (buf[8]!=0x00 || buf[9]!=0x08))) {
                    mp_msg(MSGT_DEMUX,MSGL_V,"demux_nsv: searching %.4s keyframe...\n", (char*)&priv->v_format);
                    while(((((priv->v_format>>16) & 0xff) == '6') && ((buf[8]&0x0e)!=0x06)) ||
                          ((((priv->v_format>>16) & 0xff) == '3') && (buf[8]!=0x00 || buf[9]!=0x08))){
                        mp_msg(MSGT_DEMUX,MSGL_DBG2,"demux_nsv: %.4s block skip.\n", (char*)&priv->v_format);
                        videolen=(buf[2]>>4)|(buf[3]<<4)|(buf[4]<<0xC);
                        audiolen=(buf[5])|(buf[6]<<8);
                        stream_skip(demuxer->stream, videolen+audiolen-3);
                        stream_read(demuxer->stream,buf,10);
                        if(stream_eof(demuxer->stream)) return 0;
                        if(buf[0]==0x4E){
                            mp_msg(MSGT_DEMUX,MSGL_DBG2,"demux_nsv: Got NSVs block.\n");
                            stream_skip(demuxer->stream,7);
                            stream_read(demuxer->stream,buf,10);
                        }
                    }
                }

                // data starts 10 bytes before current pos but later
                // we seek 17 backwards
                stream_skip(demuxer->stream,7);
            } 
            
        switch(priv->fps){
        case 0x80:
            sh_video->fps=30;
            break;
        case 0x81:
            sh_video->fps=(float)30000.0/1001.0;
            break;
        case 0x82:
            sh_video->fps=25;
            break;
        case 0x83:
            sh_video->fps=(float)24000.0/1001.0;
            break;
        case 0x85:
            sh_video->fps=(float)15000.0/1001.0;
            break;
        default:
            sh_video->fps = (float)priv->fps;
        }       
        sh_video->frametime = (float)1.0 / (float)sh_video->fps;
       }
    }   

    // seek to start of NSV header
    stream_seek(demuxer->stream,stream_tell(demuxer->stream)-17);
    
    return demuxer;
}

int nsv_check_file ( demuxer_t* demuxer )
{
    unsigned int id;

    /* Store original position */
//  off_t orig_pos = stream_tell(demuxer->stream);

    mp_msg ( MSGT_DEMUX, MSGL_V, "Checking for Nullsoft Streaming Video\n" );
   
    //---- check NSVx header:
    id=stream_read_dword_le(demuxer->stream);
    if(id!=mmioFOURCC('N','S','V','f') && id!=mmioFOURCC('N','S','V','s'))
        return 0; // not an NSV file
    
    stream_reset(demuxer->stream); // clear EOF
    stream_seek(demuxer->stream,demuxer->stream->start_pos);

    
    return 1;
}

void demux_close_nsv(demuxer_t* demuxer) {
    nsv_priv_t* priv = demuxer->priv;

    if(!priv)
        return;
    free(priv);

}