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
*
* WARNING: Quite a hack was required in order to get files by MultiDec played back correctly.
* If it breaks anything else, just comment out the "#define DEMUX_PVA_MULTIDEC_HACK" below
* and it will not be compiled in.
*
* Feedback is appreciated.
*
* written by Matteo Giani
*/
#define DEMUX_PVA_MULTIDEC_HACK
#define PVA_NEW_PREBYTES_CODE
#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 {
off_t offset;
long size;
uint8_t type;
uint8_t is_packet_start;
float pts;
} pva_payload_t;
typedef struct {
float last_audio_pts;
float last_video_pts;
#ifdef PVA_NEW_PREBYTES_CODE
float video_pts_after_prebytes;
long video_size_after_prebytes;
uint8_t prebytes_delivered;
#endif
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 function is used to find the next nearest PVA packet start after a seek, since a PVA file
* is not indexed.
* The just_synced field is in the priv structure so that pva_get_payload knows 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.
*/
for(count=0 ; count<PVA_MAX_VIDEO_PACK_LEN && !demuxer->stream->eof && !priv->just_synced ; 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) priv->just_synced=1;
//printf("demux_pva: pva_sync(): current offset= %ld\n",stream_tell(demuxer->stream));
}
if(priv->just_synced)
{
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;
//printf("demuxer->stream->end_pos= %d\n",demuxer->stream->end_pos);
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;
/*
printf("demuxer->video->id==%d\n",demuxer->video->id);
printf("demuxer->audio->id==%d\n",demuxer->audio->id);
*/
demuxer->audio->sh=sh_audio;
sh_audio->format=0x50;
sh_audio->ds=demuxer->audio;
demuxer->movi_start=0;
demuxer->movi_end=demuxer->stream->end_pos;
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(demux->video->id==-1) demux->video->id=0;
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(demux->video->id!=0) done=0;
if(current_payload.is_packet_start)
{
priv->last_video_pts=current_payload.pts;
//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(demux->audio->id==-1) demux->audio->id=0;
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=current_payload.pts;
}
if(demux->audio->id!=0) done=0;
if(done)
{
dp=new_demux_packet(current_payload.size);
dp->pts=priv->last_audio_pts;
if(current_payload.offset != stream_tell(demux->stream))
stream_seek(demux->stream,current_payload.offset);
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;
off_t 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)
{
mp_msg(MSGT_DEMUX,MSGL_ERR,"demux_pva: pva_get_payload got passed a NULL pointer!\n");
return 0;
}
d->filepos=stream_tell(d->stream);
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");
#ifdef PVA_NEW_PREBYTES_CODE
if(priv->prebytes_delivered)
/* The previous call to this fn has delivered the preBytes. Then we are already inside
* the payload. Let's just deliver the video along with its right PTS, the one we stored
* in the priv structure and was in the PVA header before the PreBytes.
*/
{
//printf("prebytes_delivered=1. Resetting.\n");
payload->size = priv->video_size_after_prebytes;
payload->pts = priv->video_pts_after_prebytes;
payload->is_packet_start = 1;
payload->offset = stream_tell(d->stream);
payload->type = VIDEOSTREAM;
priv->prebytes_delivered = 0;
return 1;
}
#endif
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))
{
if (!d->stream->eof)
{
mp_msg(MSGT_DEMUX,MSGL_ERR,"demux_pva: couldn't sync! (broken file?)");
}
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;
/*
* The code in the #ifdef directive below is a hack needed to get badly formatted PVA files
* such as the ones written by MultiDec played back correctly.
* Basically, it works like this: if the PVA packet does not signal a PES header, but the
* payload looks like one, let's assume it IS one. It has worked for me up to now.
* It can be disabled since it's quite an ugly hack and could potentially break things up
* if the PVA audio payload happens to start with 0x000001 even without being a non signalled
* PES header start.
* Though it's quite unlikely, it potentially could (AFAIK).
*/
#ifdef DEMUX_PVA_MULTIDEC_HACK
if(payload->type==MAINAUDIOSTREAM)
{
stream_read(d->stream,buffer,3);
if(buffer[0]==0x00 && buffer[1]==0x00 && buffer[2]==0x01 && !payload->is_packet_start)
{
mp_msg(MSGT_DEMUX,MSGL_V,"demux_pva: suspecting non signaled audio PES packet start. Maybe file by MultiDec?\n");
payload->is_packet_start=1;
}
stream_seek(d->stream,stream_tell(d->stream)-3);
}
#endif
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=(float)(le2me_32(stream_read_dword(d->stream)))/90000;
//printf("Video PTS: %f\n",payload->pts);
if((flags&0x03)
#ifdef PVA_NEW_PREBYTES_CODE
&& !priv->prebytes_delivered
#endif
)
{
#ifndef PVA_NEW_PREBYTES_CODE
dp=new_demux_packet(flags&0x03);
stream_read(d->stream,dp->buffer,flags & 0x03); //read PreBytes
ds_add_packet(d->video,dp);
#else
//printf("Delivering prebytes. Setting prebytes_delivered.");
payload->offset=stream_tell(d->stream);
payload->size = flags & 0x03;
priv->video_pts_after_prebytes = payload->pts;
priv->video_size_after_prebytes = pack_size - 4 - (flags & 0x03);
payload->pts=priv->last_video_pts;
payload->is_packet_start=0;
priv->prebytes_delivered=1;
return 1;
#endif
}
//now we are at real beginning of payload.
payload->offset=stream_tell(d->stream);
//size is pack_size minus PTS size minus PreBytes size.
payload->size=pack_size - 4 - (flags & 0x03);
break;
case MAINAUDIOSTREAM:
stream_skip(d->stream,3); //FIXME properly parse PES header.
//printf("StreamID in audio PES header: 0x%2X\n",stream_read_char(d->stream));
stream_skip(d->stream,4);
buffer[255]=stream_read_char(d->stream);
pes_head_len=stream_read_char(d->stream);
stream_read(d->stream,buffer,pes_head_len);
if(!buffer[255]&0x80) //PES header does not contain PTS.
{
mp_msg(MSGT_DEMUX,MSGL_V,"Audio PES packet does not contain PTS. (pes_head_len=%d)\n",pes_head_len);
payload->pts=priv->last_audio_pts;
break;
}
else //PES header DOES contain PTS
{
if((buffer[0] & 0xf0)!=0x20) // PTS badly formatted
{
mp_msg(MSGT_DEMUX,MSGL_V,"demux_pva: expected audio PTS but badly formatted... (read 0x%02X). Falling back to previous PTS (hack).\n",buffer[0]);
payload->pts=priv->last_audio_pts;
// return 0;
}
else
{
uint64_t temp_pts;
temp_pts=0LL;
temp_pts|=((uint64_t)(buffer[0] & 0x0e) << 29);
temp_pts|=buffer[1]<<22;
temp_pts|=(buffer[2] & 0xfe) << 14;
temp_pts|=buffer[3]<<7;
temp_pts|=(buffer[4] & 0xfe) >> 1;
/*
* PTS parsing is hopefully finished.
*/
payload->pts=(float)le2me_64(temp_pts)/90000;
}
}
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;
off_t 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;
}
}