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mpv/libmpdemux/demux_pva.c

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/*
* demuxer for PVA files, such as the ones produced by software to manage DVB boards
* like the Hauppauge WinTV DVBs, for MPlayer.
*
* Uses info from the PVA file specifications found at
*
* http://www.technotrend.de/download/av_format_v1.pdf
*
* Known issue:
* - Does not seem to correctly demux files produced by MultiDec (on some channels).
* They seem not to be correctly formatted. In fact, other DVB software which uses
* the DVB board for playback plays them fine, but existing software which should
* convert PVAs to MPEG-PS streams fails on them as well.
* Feedback would be appreciated.
*
*
* written by Matteo Giani
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "config.h"
#include "mp_msg.h"
#include "help_mp.h"
#include "stream.h"
#include "demuxer.h"
#include "stheader.h"
#include "bswap.h"
/*
* #defines below taken from PVA spec (see URL above)
*/
#define PVA_MAX_VIDEO_PACK_LEN 6*1024
#define VIDEOSTREAM 0x01
#define MAINAUDIOSTREAM 0x02
typedef struct {
unsigned long offset;
long size;
uint8_t type;
uint8_t is_packet_start;
uint64_t pts;
} pva_payload_t;
typedef struct {
float last_audio_pts;
float last_video_pts;
uint8_t just_synced;
uint8_t synced_stream_id;
} pva_priv_t;
int pva_sync(demuxer_t * demuxer)
{
uint8_t buffer[5]={0,0,0,0,0};
int count;
pva_priv_t * priv = (pva_priv_t *) demuxer->priv;
/* This is a hack. Since this function is called both for actual syncing and by
* pva_check_file to check file type, we must check whether the priv structure has
* already been allocated, otherwise we will dereference NULL and segfault.
* So, if priv is NULL (not yet allocated) use a local variable, otherwise use priv->just_synced.
* This field is in the priv structure so that pva_get_payload knows that pva_sync has already
* read (part of) the PVA header. This way we can avoid to seek back and (hopefully) be able to read
* from pipes and such.
*/
uint8_t local_synced=0;
uint8_t * syncedptr;
syncedptr=(priv==NULL)?&local_synced:&priv->just_synced;
for(count=0 ; count<PVA_MAX_VIDEO_PACK_LEN && !demuxer->stream->eof && !*syncedptr ; count++)
{
buffer[0]=buffer[1];
buffer[1]=buffer[2];
buffer[2]=buffer[3];
buffer[3]=buffer[4];
buffer[4]=stream_read_char(demuxer->stream);
/*
* Check for a PVA packet beginning sequence: we check both the "AV" word at the
* very beginning and the "0x55" reserved byte (which is unused and set to 0x55 by spec)
*/
if(buffer[0]=='A' && buffer[1] == 'V' && buffer[4] == 0x55) *syncedptr=1;
//printf("demux_pva: pva_sync() current offset: %d\n",stream_tell(demuxer->stream));
}
if(*syncedptr)
{
if(priv!=NULL) priv->synced_stream_id=buffer[2];
return 1;
}
else
{
return 0;
}
}
int pva_check_file(demuxer_t * demuxer)
{
uint8_t buffer[5]={0,0,0,0,0};
mp_msg(MSGT_DEMUX, MSGL_V, "Checking for PVA\n");
stream_read(demuxer->stream,buffer,5);
if(buffer[0]=='A' && buffer[1] == 'V' && buffer[4] == 0x55)
{
mp_msg(MSGT_DEMUX,MSGL_DBG2, "Success: PVA\n");
return 1;
}
else
{
mp_msg(MSGT_DEMUX,MSGL_DBG2, "Failed: PVA\n");
return 0;
}
}
demuxer_t * demux_open_pva (demuxer_t * demuxer)
{
sh_video_t *sh_video = new_sh_video(demuxer,0);
sh_audio_t * sh_audio = new_sh_audio(demuxer,0);
pva_priv_t * priv;
stream_reset(demuxer->stream);
stream_seek(demuxer->stream,0);
priv=malloc(sizeof(pva_priv_t));
if(demuxer->stream->type!=STREAMTYPE_FILE) demuxer->seekable=0;
else demuxer->seekable=1;
demuxer->priv=priv;
memset(demuxer->priv,0,sizeof(pva_priv_t));
if(!pva_sync(demuxer))
{
mp_msg(MSGT_DEMUX,MSGL_ERR,"Not a PVA file.\n");
return NULL;
}
//printf("priv->just_synced %s after initial sync!\n",priv->just_synced?"set":"UNSET");
demuxer->video->sh=sh_video;
demuxer->audio->sh=sh_audio;
mp_msg(MSGT_DEMUXER,MSGL_INFO,"Opened PVA demuxer...\n");
/*
* Audio and Video codecs:
* the PVA spec only allows MPEG2 video and MPEG layer II audio. No need to check the formats then.
* Moreover, there would be no way to do that since the PVA stream format has no fields to describe
* the used codecs.
*/
sh_video->format=0x10000002;
sh_video->ds=demuxer->video;
sh_audio->format=0x50;
sh_audio->ds=demuxer->audio;
priv->last_video_pts=-1;
priv->last_audio_pts=-1;
return demuxer;
}
int pva_get_payload(demuxer_t * d,pva_payload_t * payload);
// 0 = EOF or no stream found
// 1 = successfully read a packet
int demux_pva_fill_buffer (demuxer_t * demux)
{
uint8_t done=0;
demux_packet_t * dp;
pva_priv_t * priv=demux->priv;
pva_payload_t current_payload;
while(!done)
{
if(!pva_get_payload(demux,&current_payload)) return 0;
switch(current_payload.type)
{
case VIDEOSTREAM:
if(!current_payload.is_packet_start && priv->last_video_pts==-1)
{
/* We should only be here at the beginning of a stream, when we have
* not yet encountered a valid Video PTS, or after a seek.
* So, skip these starting packets in order not to deliver the
* player a bogus PTS.
*/
done=0;
}
else
{
/*
* In every other condition, we are delivering the payload. Set this
* so that the following code knows whether to skip it or read it.
*/
done=1;
}
if(current_payload.is_packet_start)
{
priv->last_video_pts=((float)current_payload.pts)/90000;
//mp_msg(MSGT_DEMUXER,MSGL_DBG2,"demux_pva: Video PTS=%llu , delivered %f\n",current_payload.pts,priv->last_video_pts);
}
if(done)
{
dp=new_demux_packet(current_payload.size);
dp->pts=priv->last_video_pts;
stream_read(demux->stream,dp->buffer,current_payload.size);
ds_add_packet(demux->video,dp);
}
else
{
//printf("Skipping %u video bytes\n",current_payload.size);
stream_skip(demux->stream,current_payload.size);
}
break;
case MAINAUDIOSTREAM:
if(!current_payload.is_packet_start && priv->last_audio_pts==-1)
{
/* Same as above for invalid video PTS, just for audio. */
done=0;
}
else
{
done=1;
}
if(current_payload.is_packet_start)
{
priv->last_audio_pts=(float)current_payload.pts/90000;
}
if(done)
{
dp=new_demux_packet(current_payload.size);
dp->pts=priv->last_audio_pts;
stream_read(demux->stream,dp->buffer,current_payload.size);
ds_add_packet(demux->audio,dp);
}
else
{
stream_skip(demux->stream,current_payload.size);
}
break;
}
}
return 1;
}
int pva_get_payload(demuxer_t * d,pva_payload_t * payload)
{
uint8_t flags,pes_head_len;
uint16_t pack_size;
long long next_offset,pva_payload_start;
unsigned char buffer[256];
demux_packet_t * dp; //hack to deliver the preBytes (see PVA doc)
pva_priv_t * priv=(pva_priv_t *) d->priv;
if(d==NULL)
{
printf("demux_pva: pva_get_payload got passed a NULL pointer!\n");
return 0;
}
if(d->stream->eof)
{
mp_msg(MSGT_DEMUX,MSGL_V,"demux_pva: pva_get_payload() detected stream->eof!!!\n");
return 0;
}
//printf("priv->just_synced %s\n",priv->just_synced?"SET":"UNSET");
if(!priv->just_synced)
{
if(stream_read_word(d->stream) != (('A'<<8)|'V'))
{
mp_msg(MSGT_DEMUX,MSGL_V,"demux_pva: pva_get_payload() missed a SyncWord at %ld!! Trying to sync...\n",stream_tell(d->stream));
if(!pva_sync(d)) return 0;
}
}
if(priv->just_synced)
{
payload->type=priv->synced_stream_id;
priv->just_synced=0;
}
else
{
payload->type=stream_read_char(d->stream);
stream_skip(d->stream,2); //counter and reserved
}
flags=stream_read_char(d->stream);
payload->is_packet_start=flags & 0x10;
pack_size=le2me_16(stream_read_word(d->stream));
mp_msg(MSGT_DEMUX,MSGL_DBG2,"demux_pva::pva_get_payload(): pack_size=%u field read at offset %lu\n",pack_size,stream_tell(d->stream)-2);
pva_payload_start=stream_tell(d->stream);
next_offset=pva_payload_start+pack_size;
if(!payload->is_packet_start)
{
payload->offset=stream_tell(d->stream);
payload->size=pack_size;
}
else
{ //here comes the good part...
switch(payload->type)
{
case VIDEOSTREAM:
payload->pts=le2me_32(stream_read_dword(d->stream));
//printf("Video PTS: %llu\n",payload->pts);
if((flags&0x03) && ((pva_priv_t *)d->priv)->last_video_pts!=-1)
{
dp=new_demux_packet(flags&0x03);
stream_read(d->stream,dp->buffer,flags & 0x03); //read PreBytes
dp->pts=((pva_priv_t *)d->priv)->last_video_pts;
ds_add_packet(d->video,dp);
}
else
{
stream_skip(d->stream,flags&0x03);
}
//now we are at real beginning of payload.
payload->offset=stream_tell(d->stream);
//size is pack_size minus PTS size minus padding size.
payload->size=pack_size - 4 - (flags & 0x03);
break;
case MAINAUDIOSTREAM:
stream_skip(d->stream,8); //FIXME properly parse PES header.
//assuming byte 8 is PES residual header length.
pes_head_len=stream_read_char(d->stream);
stream_read(d->stream,buffer,pes_head_len);
//we should now be on start of real payload.
//let's now parse the PTS...
if((buffer[0] & 0xf0)!=0x20)
{
mp_msg(MSGT_DEMUX,MSGL_ERR,"demux_pva: expected audio PTS but badly formatted... (read 0x%02X)\n",buffer[0]);
return 0;
}
payload->pts=0LL;
payload->pts|=((uint64_t)(buffer[0] & 0x0e) << 29);
payload->pts|=buffer[1]<<22;
payload->pts|=(buffer[2] & 0xfe) << 14;
payload->pts|=buffer[3]<<7;
payload->pts|=(buffer[4] & 0xfe) >> 1;
/*
* PTS parsing is hopefully finished.
* Let's now fill in offset and size.
*/
payload->pts=le2me_64(payload->pts);
payload->offset=stream_tell(d->stream);
payload->size=pack_size-stream_tell(d->stream)+pva_payload_start;
break;
}
}
return 1;
}
int demux_seek_pva(demuxer_t * demuxer,float rel_seek_secs,int flags)
{
int total_bitrate=0;
long dest_offset;
pva_priv_t * priv=demuxer->priv;
total_bitrate=((sh_audio_t *)demuxer->audio->sh)->i_bps + ((sh_video_t *)demuxer->video->sh)->i_bps;
/*
* Compute absolute offset inside the stream. Approximate total bitrate with sum of bitrates
* reported by the audio and video codecs. The seek is not accurate because, just like
* with MPEG streams, the bitrate is not constant. Moreover, we do not take into account
* the overhead caused by PVA and PES headers.
* If the calculated absolute offset is negative, seek to the beginning of the file.
*/
dest_offset=stream_tell(demuxer->stream)+rel_seek_secs*total_bitrate;
if(dest_offset<0) dest_offset=0;
stream_seek(demuxer->stream,dest_offset);
if(!pva_sync(demuxer))
{
mp_msg(MSGT_DEMUX,MSGL_V,"demux_pva: Couldn't seek!\n");
return 0;
}
/*
* Reset the PTS info inside the pva_priv_t structure. This way we don't deliver
* data with the wrong PTSs (the ones we had before seeking).
*
*/
priv->last_video_pts=-1;
priv->last_audio_pts=-1;
return 1;
}
void demux_close_pva(demuxer_t * demuxer)
{
if(demuxer->priv)
{
free(demuxer->priv);
demuxer->priv=NULL;
}
}