Apr 9, 2019, 2:56 PM by d...@lynne.ee: > > > > Apr 7, 2019, 12:56 AM by > mich...@niedermayer.cc > <mailto:mich...@niedermayer.cc>> : > >> On Sat, Apr 06, 2019 at 10:44:00AM +0200, Lynne wrote: >> >>> Apr 4, 2019, 10:30 AM by >>> mich...@niedermayer.cc >>> <mailto: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>>>> >>> >> <mailto:>>> 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>>>> <mailto:>>> >>> >> 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 ... >> > > I think skipping the check for such files is okay for now. Its just for > verification purposes after all, and not all decoders implement the option > but silently skip it. >
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