On Sat, Apr 06, 2019 at 10:44:00AM +0200, Lynne wrote: > Apr 4, 2019, 10:30 AM by mich...@niedermayer.cc: > > > On Wed, Mar 06, 2019 at 02:47:37PM +0100, Lynne wrote: > > > >> 6 Mar 2019, 11:22 by >> d...@lynne.ee <mailto:d...@lynne.ee>>> : > >> > >> > The CRC flag is only signalled once every few minutes but CRC is still > >> > always present so the patch uses the file version instead. > >> > CRC on 24-bit files wants non-padded samples so skip such files. > >> > Some corrupt samples may have been output before the final check > >> > depending on the -max_samples setting. > >> > > >> v2 attached > >> > >> apedec.c | 26 +++++++++++++++++++++++++- > >> 1 file changed, 25 insertions(+), 1 deletion(-) > >> c0cc550d77927ee0349094a4976f73d0ef671ff6 > >> 0001-apedec-add-ability-to-check-CRC-v2.patch > >> From 68c25bb026761eacda3c276148e2beb34e8929fd Mon Sep 17 00:00:00 2001 > >> From: Lynne <>> d...@lynne.ee <mailto:d...@lynne.ee>>> > > >> Date: Wed, 6 Mar 2019 11:01:01 +0000 > >> Subject: [PATCH v2] apedec: add ability to check CRC > >> > >> The CRC flag is only signalled once every few minutes but CRC is still > >> always present so the patch uses the file version instead. > >> CRC on 24-bit files wants non-padded samples so skip such files. > >> Some corrupt samples may have been output before the final check > >> depending on the -max_samples setting. > >> --- > >> libavcodec/apedec.c | 26 +++++++++++++++++++++++++- > >> 1 file changed, 25 insertions(+), 1 deletion(-) > >> > >> diff --git a/libavcodec/apedec.c b/libavcodec/apedec.c > >> index 15eb416ba4..a20d884606 100644 > >> --- a/libavcodec/apedec.c > >> +++ b/libavcodec/apedec.c > >> @@ -24,6 +24,7 @@ > >> > >> #include "libavutil/avassert.h" > >> #include "libavutil/channel_layout.h" > >> +#include "libavutil/crc.h" > >> #include "libavutil/opt.h" > >> #include "lossless_audiodsp.h" > >> #include "avcodec.h" > >> @@ -147,7 +148,8 @@ typedef struct APEContext { > >> int fset; ///< which filter set to use > >> (calculated from compression level) > >> int flags; ///< global decoder flags > >> > >> - uint32_t CRC; ///< frame CRC > >> + uint32_t CRC; ///< signalled frame CRC > >> + uint32_t CRC_state; ///< accumulated CRC > >> int frameflags; ///< frame flags > >> APEPredictor predictor; ///< predictor used for final > >> reconstruction > >> > >> @@ -730,6 +732,7 @@ static int init_entropy_decoder(APEContext *ctx) > >> > >> /* Read the frame flags if they exist */ > >> ctx->frameflags = 0; > >> + ctx->CRC_state = UINT32_MAX; > >> if ((ctx->fileversion > 3820) && (ctx->CRC & 0x80000000)) { > >> ctx->CRC &= ~0x80000000; > >> > >> @@ -1548,6 +1551,27 @@ static int ape_decode_frame(AVCodecContext *avctx, > >> void *data, > >> > >> s->samples -= blockstodecode; > >> > >> + if ((avctx->err_recognition & AV_EF_CRCCHECK) && > >> > >> + (s->fileversion >= 3900) && (s->bps < 24)) { > >> > > > > what about file versions other than this ? do they have no crc ? > > > They have a different CRC version which is poorly documented. > > >
> > > > what about othet bps ? > > > 24 bit CRC needs to ignore the zeroes padding each sample in 32 bits. I > couldn't find any 24-bit files so I left that for a future patch. can such a file not be generated ? or maybe printing a note and asking for a sample in this case would be an option if noone has one either ... [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Let us carefully observe those good qualities wherein our enemies excel us and endeavor to excel them, by avoiding what is faulty, and imitating what is excellent in them. -- Plutarch
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