On Thu, Jun 19, 2014 at 03:30:06PM +0200, Miroslav Lichvar wrote:
> But, as we have seen with unusual data the residual signal can be
> wider than bps. The FLAC format specification doesn't seem to mention
> this. Should it be treated as a valid FLAC stream?
I think it would be interesting to know how common are such streams. I
patched flac to print a warning on decoding or testing when this is
detected, but didn't find any files with this problem in my (small)
music collection.
If someone has a large collection and some cycles to spare, can you please
consider compiling flac from git with the attached patch and see if
you have any files that fail with "flac -t" ?
With the known problem file (snippet6.wav) encoded by 1.3.0 it prints
this:
WARNING: residual -11025151 wider than bps 24
WARNING: residual 41873263 wider than bps 24
WARNING: residual -67175215 wider than bps 24
WARNING: residual 69950995 wider than bps 24
WARNING: residual -67108864 wider than bps 24
...
WARNING: residual 11227392 wider than bps 24
WARNING: residual -8754288 wider than bps 24
snippet6.flac: ERROR, MD5 signature mismatch
Thanks,
--
Miroslav Lichvar
diff --git a/src/libFLAC/stream_decoder.c b/src/libFLAC/stream_decoder.c
index ddd8979..82318ae 100644
--- a/src/libFLAC/stream_decoder.c
+++ b/src/libFLAC/stream_decoder.c
@@ -99,7 +99,7 @@ static FLAC__bool read_subframe_constant_(FLAC__StreamDecoder
*decoder, unsigned
static FLAC__bool read_subframe_fixed_(FLAC__StreamDecoder *decoder, unsigned
channel, unsigned bps, const unsigned order, FLAC__bool do_full_decode);
static FLAC__bool read_subframe_lpc_(FLAC__StreamDecoder *decoder, unsigned
channel, unsigned bps, const unsigned order, FLAC__bool do_full_decode);
static FLAC__bool read_subframe_verbatim_(FLAC__StreamDecoder *decoder,
unsigned channel, unsigned bps, FLAC__bool do_full_decode);
-static FLAC__bool read_residual_partitioned_rice_(FLAC__StreamDecoder
*decoder, unsigned predictor_order, unsigned partition_order,
FLAC__EntropyCodingMethod_PartitionedRiceContents *partitioned_rice_contents,
FLAC__int32 *residual, FLAC__bool is_extended);
+static FLAC__bool read_residual_partitioned_rice_(FLAC__StreamDecoder
*decoder, unsigned predictor_order, unsigned partition_order,
FLAC__EntropyCodingMethod_PartitionedRiceContents *partitioned_rice_contents,
FLAC__int32 *residual, FLAC__bool is_extended, int bps);
static FLAC__bool read_zero_padding_(FLAC__StreamDecoder *decoder);
static FLAC__bool read_callback_(FLAC__byte buffer[], size_t *bytes, void
*client_data);
#if FLAC__HAS_OGG
@@ -2572,7 +2572,7 @@ FLAC__bool read_subframe_fixed_(FLAC__StreamDecoder
*decoder, unsigned channel,
switch(subframe->entropy_coding_method.type) {
case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE:
case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE2:
- if(!read_residual_partitioned_rice_(decoder, order,
subframe->entropy_coding_method.data.partitioned_rice.order,
&decoder->private_->partitioned_rice_contents[channel],
decoder->private_->residual[channel],
/*is_extended=*/subframe->entropy_coding_method.type ==
FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE2))
+ if(!read_residual_partitioned_rice_(decoder, order,
subframe->entropy_coding_method.data.partitioned_rice.order,
&decoder->private_->partitioned_rice_contents[channel],
decoder->private_->residual[channel],
/*is_extended=*/subframe->entropy_coding_method.type ==
FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE2, bps))
return false;
break;
default:
@@ -2651,7 +2651,7 @@ FLAC__bool read_subframe_lpc_(FLAC__StreamDecoder
*decoder, unsigned channel, un
switch(subframe->entropy_coding_method.type) {
case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE:
case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE2:
- if(!read_residual_partitioned_rice_(decoder, order,
subframe->entropy_coding_method.data.partitioned_rice.order,
&decoder->private_->partitioned_rice_contents[channel],
decoder->private_->residual[channel],
/*is_extended=*/subframe->entropy_coding_method.type ==
FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE2))
+ if(!read_residual_partitioned_rice_(decoder, order,
subframe->entropy_coding_method.data.partitioned_rice.order,
&decoder->private_->partitioned_rice_contents[channel],
decoder->private_->residual[channel],
/*is_extended=*/subframe->entropy_coding_method.type ==
FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE2, bps))
return false;
break;
default:
@@ -2703,7 +2703,7 @@ FLAC__bool read_subframe_verbatim_(FLAC__StreamDecoder
*decoder, unsigned channe
return true;
}
-FLAC__bool read_residual_partitioned_rice_(FLAC__StreamDecoder *decoder,
unsigned predictor_order, unsigned partition_order,
FLAC__EntropyCodingMethod_PartitionedRiceContents *partitioned_rice_contents,
FLAC__int32 *residual, FLAC__bool is_extended)
+FLAC__bool read_residual_partitioned_rice_(FLAC__StreamDecoder *decoder,
unsigned predictor_order, unsigned partition_order,
FLAC__EntropyCodingMethod_PartitionedRiceContents *partitioned_rice_contents,
FLAC__int32 *residual, FLAC__bool is_extended, int bps)
{
FLAC__uint32 rice_parameter;
int i;
@@ -2744,6 +2744,15 @@ FLAC__bool
read_residual_partitioned_rice_(FLAC__StreamDecoder *decoder, unsigne
u = (partition_order == 0 || partition > 0)?
partition_samples : partition_samples - predictor_order;
if(!decoder->private_->local_bitreader_read_rice_signed_block(decoder->private_->input,
residual + sample, u, rice_parameter))
return false; /* read_callback_ sets the state
for us */
+#if 1
+ for (i = sample; (unsigned)i < sample + u; i++) {
+ if (abs(residual[i]) > (1 << (bps - 1))) {
+ fprintf(stderr, "WARNING: residual %d
wider than bps %d\n",
+ residual[i], bps);
+ residual[i]--; /* corrupt the value to
fail decoding test */
+ }
+ }
+#endif
sample += u;
}
else {
_______________________________________________
flac-dev mailing list
flac-dev@xiph.org
http://lists.xiph.org/mailman/listinfo/flac-dev
