diff options
| author | Richard van der Hoff <richardv@mxtelecom.com> | 2007-08-21 22:00:06 +0000 |
|---|---|---|
| committer | Richard van der Hoff <richardv@mxtelecom.com> | 2007-08-21 22:00:06 +0000 |
| commit | e6002deb3e16a050f664a325c5e2c056ca730c64 (patch) | |
| tree | e629d7b408dd5176230787a9596c914ec649180b /wiretap/mpeg.c | |
| parent | 32d553796646f47bc5ae6fa778030a2b35d3b8ed (diff) | |
From Shaun Jackman <sjackman@gmail.com> / bug 1753:
* asn1/mpeg/packet-mpeg-pes-template.c: Improved decoding of PES
extension header and Pack header. Decode SCR, PTS, and DTS.
* asn1/mpeg/mpeg-pes.asn (Pack): Remove.
* epan/dissectors/packet-mpeg-pes.c: Regenerate.
* wiretap/mpeg.c (mpeg_read): Decode the SCR using integer
arithmetic instead of double float arithmetic to prevent rounding
error.
* wiretap/wtap-int.h (mpeg_t) <t0>: Use time_t instead of double.
svn path=/trunk/; revision=22577
Diffstat (limited to 'wiretap/mpeg.c')
| -rw-r--r-- | wiretap/mpeg.c | 32 |
1 files changed, 17 insertions, 15 deletions
diff --git a/wiretap/mpeg.c b/wiretap/mpeg.c index 2e462a5753..d303023353 100644 --- a/wiretap/mpeg.c +++ b/wiretap/mpeg.c @@ -41,7 +41,6 @@ #include "buffer.h" #include "file_wrappers.h" #include <errno.h> -#include <math.h> #include <stdlib.h> #include <string.h> #include <time.h> @@ -106,6 +105,8 @@ mpeg_read_rec_data(FILE_T fh, guchar *pd, int length, int *err) return TRUE; } +#define SCRHZ 27000000 + static gboolean mpeg_read(wtap *wth, int *err, gchar **err_info _U_, gint64 *data_offset) @@ -138,10 +139,6 @@ mpeg_read(wtap *wth, int *err, gchar **err_info _U_, guint32 pack0; guint64 pack; guint8 stuffing; - guint32 scr; - guint16 scr_ext; - double t; - double secs; bytes_read = file_read(&pack1, 1, sizeof pack1, wth->fh); if (bytes_read != sizeof pack1) { @@ -172,15 +169,20 @@ mpeg_read(wtap *wth, int *err, gchar **err_info _U_, stuffing &= 0x07; packet_size = 14 + stuffing; - scr = (guint32) - ((pack >> 59 & 0x0007) << 30 | - (pack >> 43 & 0x7fff) << 15 | - (pack >> 27 & 0x7fff) << 0); - scr_ext = (guint16)(pack >> 17 & 0x1ff); - t = wth->capture.mpeg->t0 + scr / 90e3 + scr_ext / 27e6; - - wth->capture.mpeg->now.nsecs = (int)(modf(t, &secs) * 1e9); - wth->capture.mpeg->now.secs = (time_t)secs; + { + guint64 bytes = pack >> 16; + guint64 ts = + (bytes >> 43 & 0x0007) << 30 | + (bytes >> 27 & 0x7fff) << 15 | + (bytes >> 11 & 0x7fff) << 0; + unsigned ext = bytes >> 1 & 0x1ff; + guint64 cr = 300 * ts + ext; + unsigned rem = cr % SCRHZ; + wth->capture.mpeg->now.secs + = wth->capture.mpeg->t0 + cr / SCRHZ; + wth->capture.mpeg->now.nsecs + = 1000000000LL * rem / SCRHZ; + } ts = wth->capture.mpeg->now; break; default: @@ -297,7 +299,7 @@ good_magic: wth->capture.mpeg = g_malloc(sizeof(mpeg_t)); wth->capture.mpeg->now.secs = time(NULL); wth->capture.mpeg->now.nsecs = 0; - wth->capture.mpeg->t0 = (double) wth->capture.mpeg->now.secs; + wth->capture.mpeg->t0 = wth->capture.mpeg->now.secs; return 1; } |