stream: kill start_pos, remove --sb option

stream.start_pos was needed for optical media only, and (apparently) not
for very good reasons. Just get rid of it.

For stream_dvd, we don't need to do anything. Byte seeking was already
removed from it earlier.

For stream_cdda and stream_vcd, emulate the start_pos by offsetting the
stream pos as seen by the rest of mpv.

The bits in discnav.c and loadfile.c were for dealing with the code
seeking back to the start in demux.c. Handle this differently by
assuming the demuxer is always initialized with the stream at start
position, and instead seek back if initializing the demuxer fails.

Remove the --sb option, which worked by modifying stream.start_pos. If
someone really wants this option, it could be added back by creating a
"slice" stream (actually ffmpeg already has such a thing).

9 files changed, 17 insertions, 9 deletions

diff --git a/stream/stream.c b/stream/stream.c
index b6fec81eb8..0acabe3f52 100644
--- a/stream/stream.c
+++ b/stream/stream.c
@@ -815,7 +815,6 @@ int stream_enable_cache(stream_t **stream, struct mp_cache_opts *opts)
     cache->safe_origin = orig->safe_origin;
     cache->opts = orig->opts;
     cache->global = orig->global;
-    cache->start_pos = orig->start_pos;
     cache->end_pos = orig->end_pos;
 
     cache->log = mp_log_new(cache, cache->global->log, "cache");
diff --git a/stream/stream.h b/stream/stream.h
index 3675ea9732..2182de2526 100644
--- a/stream/stream.h
+++ b/stream/stream.h
@@ -147,7 +147,7 @@ typedef struct stream {
     int sector_size; // sector size (seek will be aligned on this size if non 0)
     int read_chunk; // maximum amount of data to read at once to limit latency
     unsigned int buf_pos, buf_len;
-    int64_t pos, start_pos, end_pos;
+    int64_t pos, end_pos;
     int eof;
     int mode; //STREAM_READ or STREAM_WRITE
     bool streaming;     // known to be a network stream if true
diff --git a/stream/stream_cdda.c b/stream/stream_cdda.c
index 1b81bfc6fb..6f1c747483 100644
--- a/stream/stream_cdda.c
+++ b/stream/stream_cdda.c
@@ -202,6 +202,8 @@ static int seek(stream_t *s, int64_t newpos)
     int seek_to_track = 0;
     int i;
 
+    newpos += priv->start_sector * CDIO_CD_FRAMESIZE_RAW;
+
     sec = newpos / CDIO_CD_FRAMESIZE_RAW;
     if (newpos < 0 || sec > p->end_sector) {
         p->sector = p->end_sector + 1;
@@ -388,8 +390,8 @@ static int open_cdda(stream_t *st, int m)
     priv->sector = priv->start_sector;
 
     st->priv = priv;
-    st->start_pos = priv->start_sector * CDIO_CD_FRAMESIZE_RAW;
-    st->end_pos = (priv->end_sector + 1) * CDIO_CD_FRAMESIZE_RAW;
+    st->end_pos =
+        (priv->end_sector + 1 - priv->start_sector) * CDIO_CD_FRAMESIZE_RAW;
     st->sector_size = CDIO_CD_FRAMESIZE_RAW;
 
     st->fill_buffer = fill_buffer;
diff --git a/stream/stream_dvd.c b/stream/stream_dvd.c
index 0394a2640c..c393915ffd 100644
--- a/stream/stream_dvd.c
+++ b/stream/stream_dvd.c
@@ -918,7 +918,6 @@ static int open_s(stream_t *stream, int mode)
     stream->fill_buffer = fill_buffer;
     stream->control = control;
     stream->close = stream_dvd_close;
-    stream->start_pos = (int64_t)d->cur_pack*2048;
     stream->end_pos = (int64_t)(d->cur_pgc->cell_playback[d->last_cell-1].last_sector)*2048;
     MP_VERBOSE(stream, "DVD start=%d end=%d  \n",d->cur_pack,d->cur_pgc->cell_playback[d->last_cell-1].last_sector);
     stream->priv = (void*)d;
diff --git a/stream/stream_vcd.c b/stream/stream_vcd.c
index c0da02a324..a61fc04376 100644
--- a/stream/stream_vcd.c
+++ b/stream/stream_vcd.c
@@ -59,7 +59,7 @@
 #include "osdep/io.h"
 
 static int fill_buffer(stream_t *s, char* buffer, int max_len){
-  if(s->pos > s->end_pos) /// don't past end of current track
+  if(s->pos > s->end_pos) /// don't read past end of current track
     return 0;
   if (max_len < VCD_SECTOR_DATA)
     return -1;
@@ -67,7 +67,9 @@ static int fill_buffer(stream_t *s, char* buffer, int max_len){
 }
 
 static int seek(stream_t *s,int64_t newpos) {
-  vcd_set_msf(s->priv,newpos/VCD_SECTOR_DATA);
+  mp_vcd_priv_t *vcd = s->priv;
+  newpos += vcd->start;
+  vcd_set_msf(vcd,newpos/VCD_SECTOR_DATA);
   return 1;
 }
 
@@ -162,8 +164,7 @@ static int open_s(stream_t *stream,int mode)
 #endif
 
   stream->sector_size = VCD_SECTOR_DATA;
-  stream->start_pos=ret;
-  stream->end_pos=ret2;
+  stream->end_pos=ret2-ret;
   stream->priv = vcd;
 
   stream->fill_buffer = fill_buffer;
@@ -171,6 +172,9 @@ static int open_s(stream_t *stream,int mode)
   stream->close = close_s;
   stream->demuxer = "lavf"; // mpegps ( or "vcd"?)
 
+  vcd->start = ret;
+  seek(stream, 0);
+
   return STREAM_OK;
 }
 
diff --git a/stream/vcd_read.h b/stream/vcd_read.h
index ccb176ff97..5a5d033f4b 100644
--- a/stream/vcd_read.h
+++ b/stream/vcd_read.h
@@ -42,6 +42,7 @@ static int sun_vcd_read(mp_vcd_priv_t*, int*);
 #endif
 
 struct mp_vcd_priv_st {
+  int start;
   stream_t *stream;
   int fd;
   struct cdrom_tocentry entry;
diff --git a/stream/vcd_read_darwin.h b/stream/vcd_read_darwin.h
index ecfe596f51..f35717856a 100644
--- a/stream/vcd_read_darwin.h
+++ b/stream/vcd_read_darwin.h
@@ -50,6 +50,7 @@ typedef struct
 
 typedef struct mp_vcd_priv_st
 {
+        int start;
         stream_t *stream;
         int fd;
         cdsector_t buf;
diff --git a/stream/vcd_read_fbsd.h b/stream/vcd_read_fbsd.h
index ffa9ae7f6d..8f7f2a585a 100644
--- a/stream/vcd_read_fbsd.h
+++ b/stream/vcd_read_fbsd.h
@@ -61,6 +61,7 @@ typedef struct ioc_read_toc_single_entry vcd_tocentry;
 #endif
 
 typedef struct mp_vcd_priv_st {
+  int start;
   int fd;
   vcd_tocentry entry;
 #ifdef VCD_NETBSD
diff --git a/stream/vcd_read_win32.h b/stream/vcd_read_win32.h
index ac6466c2a1..a01290eeb9 100644
--- a/stream/vcd_read_win32.h
+++ b/stream/vcd_read_win32.h
@@ -34,6 +34,7 @@ typedef struct mp_vcd_priv_st mp_vcd_priv_t;
    we cache the information in mp_vcd_priv_st.
 */
 struct mp_vcd_priv_st {
+    int start;
     HANDLE hd;
     CDROM_TOC toc;
     unsigned sect;