From aa6fec669ef750837d3e4e3bdb903879b392caba Mon Sep 17 00:00:00 2001
From: "Timothy B. Terriberry" <tterribe@xiph.org>
Date: Tue, 1 Feb 2011 15:36:59 -0800
Subject: [PATCH] Limit mode creation to supported modes.
We did no real error checking to see if a mode is supported when it
is created.
This patch implements checks for Jean-Marc's rules:
1) A mode must have frames at least 1ms in length (no more than
1000 per second).
2) A mode must have shorts of at most 3.33 ms (at least 300 per
second).
It also adds error checking to dump_modes so we report the error
instead of crashing when we fail to create a mode.
---
libcelt/dump_modes.c | 7 +++++++
libcelt/modes.c | 44 +++++++++++++++++++++++++++++---------------
2 files changed, 36 insertions(+), 15 deletions(-)
diff --git a/libcelt/dump_modes.c b/libcelt/dump_modes.c
index 340dcfca..ac2e88b6 100644
--- a/libcelt/dump_modes.c
+++ b/libcelt/dump_modes.c
@@ -34,6 +34,7 @@
#include "config.h"
#endif
+#include <stdlib.h>
#include <stdio.h>
#include "modes.h"
#include "celt.h"
@@ -308,6 +309,12 @@ int main(int argc, char **argv)
Fs = atoi(argv[2*i+1]);
frame = atoi(argv[2*i+2]);
m[i] = celt_mode_create(Fs, frame, NULL);
+ if (m[i]==NULL)
+ {
+ fprintf(stderr,"Error creating mode with Fs=%s, frame_size=%s\n",
+ argv[2*i+1],argv[2*i+2]);
+ return EXIT_FAILURE;
+ }
}
file = fopen(BASENAME ".c", "w");
dump_modes(file, m, nb);
diff --git a/libcelt/modes.c b/libcelt/modes.c
index 259a49bc..6414d2fc 100644
--- a/libcelt/modes.c
+++ b/libcelt/modes.c
@@ -331,7 +331,35 @@ CELTMode *celt_mode_create(celt_int32 Fs, int frame_size, int *error)
*error = CELT_BAD_ARG;
return NULL;
}
-
+ /* Frames of less than 1ms are not supported. */
+ if ((celt_int32)frame_size*1000 < Fs)
+ {
+ if (error)
+ *error = CELT_INVALID_MODE;
+ return NULL;
+ }
+
+ if ((celt_int32)frame_size*75 >= Fs && (frame_size%16)==0)
+ {
+ LM = 3;
+ } else if ((celt_int32)frame_size*150 >= Fs && (frame_size%8)==0)
+ {
+ LM = 2;
+ } else if ((celt_int32)frame_size*300 >= Fs && (frame_size%4)==0)
+ {
+ LM = 1;
+ } else if ((celt_int32)frame_size*300 <= Fs)
+ {
+ LM = 0;
+ }
+ /* Shorts longer than 3.3ms are not supported. */
+ else
+ {
+ if (error)
+ *error = CELT_INVALID_MODE;
+ return NULL;
+ }
+
mode = celt_alloc(sizeof(CELTMode));
if (mode==NULL)
goto failure;
@@ -366,20 +394,6 @@ CELTMode *celt_mode_create(celt_int32 Fs, int frame_size, int *error)
mode->preemph[3] = QCONST16(1.f, 13);
}
- if ((celt_int32)frame_size*75 >= Fs && (frame_size%16)==0)
- {
- LM = 3;
- } else if ((celt_int32)frame_size*150 >= Fs && (frame_size%8)==0)
- {
- LM = 2;
- } else if ((celt_int32)frame_size*300 >= Fs && (frame_size%4)==0)
- {
- LM = 1;
- } else
- {
- LM = 0;
- }
-
mode->maxLM = LM;
mode->nbShortMdcts = 1<<LM;
mode->shortMdctSize = frame_size/mode->nbShortMdcts;
--
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