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Fix issues in BitstreamConverter #23174

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Fix issues in BitstreamConverter #23174

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f3778e7
BitstreamConverter: fix signed/unsigned mismatches and a pointer arit…
tanio99 Apr 9, 2020
429f6ab
BitstreamConverter: also parse mvcC atom if it's present in the extra…
tanio99 Aug 29, 2019
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23 changes: 18 additions & 5 deletions xbmc/utils/BitstreamConverter.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -535,7 +535,7 @@ bool CBitstreamConverter::Convert(uint8_t *pData, int iSize)
if (m_convert_bitstream)
{
// convert demuxer packet from bitstream to bytestream (AnnexB)
int bytestream_size = 0;
uint32_t bytestream_size = 0;
uint8_t *bytestream_buff = NULL;

BitstreamConvert(demuxer_content, demuxer_bytes, &bytestream_buff, &bytestream_size);
Expand Down Expand Up @@ -678,6 +678,7 @@ bool CBitstreamConverter::BitstreamConvertInitAVC(void *in_extradata, int in_ext
uint16_t unit_size;
uint32_t total_size = 0;
uint8_t *out = NULL, unit_nb, sps_done = 0, sps_seen = 0, pps_seen = 0;
uint8_t mvc_done = 0;
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Suggested change
uint8_t mvc_done = 0;
bool mvcDone{false};

const uint8_t *extradata = (uint8_t*)in_extradata + 4;
static const uint8_t nalu_header[4] = {0, 0, 0, 1};

Expand Down Expand Up @@ -726,6 +727,18 @@ bool CBitstreamConverter::BitstreamConvertInitAVC(void *in_extradata, int in_ext
if (unit_nb)
pps_seen = 1;
}

if (!unit_nb && !mvc_done++)
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I know you were following the pattern but generally ints either need to be compared directly or casted to bool. I also recommend using a bool when wanting a boolean check.

Suggested change
if (!unit_nb && !mvc_done++)
if (unit_nb == 0 && !mvc_done)

{
if (in_extrasize - total_size > 14 && memcmp(extradata + 8, "mvcC", 4) == 0)
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Generally magic numbers are frowned upon. Please use constexpr int's to help with human readable values. In reality it would just be nice if we could define a structure for the extradata so we don't need to do all this magic number jumping around but I'll leave that as a future wish.

Suggested change
if (in_extrasize - total_size > 14 && memcmp(extradata + 8, "mvcC", 4) == 0)
constexpr int MINIMUM_SIZE{14};
constexpr int HEADER_OFFSET{8};
if (in_extrasize - total_size > MINIMUM_SIZE && memcmp(extradata + HEADER_OFFSET, "mvcC", strlen("mvcC")) == 0)

{
// start over; take SPS and PPS from the mvcC atom
extradata += 12 + 5; // skip over mvcC atom header
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magic everywhere!

unit_nb = *extradata++ & 0x1f; // number of sps unit(s)
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more magic?

sps_done = 0;
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It would be a gold star if you could (possibly in a future PR) convert these to bool.

pps_seen = 0;
}
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Suggested change
}
mvcDone = true;
}

}
}

if (out)
Expand Down Expand Up @@ -868,7 +881,7 @@ bool CBitstreamConverter::IsSlice(uint8_t unit_type)
}
}

bool CBitstreamConverter::BitstreamConvert(uint8_t* pData, int iSize, uint8_t **poutbuf, int *poutbuf_size)
bool CBitstreamConverter::BitstreamConvert(uint8_t* pData, int iSize, uint8_t **poutbuf, uint32_t *poutbuf_size)
{
// based on h264_mp4toannexb_bsf.c (ffmpeg)
// which is Copyright (c) 2007 Benoit Fouet <benoit.fouet@free.fr>
Expand All @@ -878,7 +891,7 @@ bool CBitstreamConverter::BitstreamConvert(uint8_t* pData, int iSize, uint8_t **
uint8_t *buf = pData;
uint32_t buf_size = iSize;
uint8_t unit_type, nal_sps, nal_pps, nal_sei;
int32_t nal_size;
uint32_t nal_size;
uint32_t cumul_size = 0;
const uint8_t *buf_end = buf + buf_size;

Expand Down Expand Up @@ -916,7 +929,7 @@ bool CBitstreamConverter::BitstreamConvert(uint8_t* pData, int iSize, uint8_t **
unit_type = (*buf >> 1) & 0x3f;
}

if (buf + nal_size > buf_end || nal_size <= 0)
if (nal_size > (buf_end - buf) || nal_size == 0)
goto fail;

// Don't add sps/pps if the unit already contain them
Expand Down Expand Up @@ -956,7 +969,7 @@ bool CBitstreamConverter::BitstreamConvert(uint8_t* pData, int iSize, uint8_t **
}

void CBitstreamConverter::BitstreamAllocAndCopy(uint8_t** poutbuf,
int* poutbuf_size,
uint32_t* poutbuf_size,
const uint8_t* sps_pps,
uint32_t sps_pps_size,
const uint8_t* in,
Expand Down
4 changes: 2 additions & 2 deletions xbmc/utils/BitstreamConverter.h
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Original file line number Diff line number Diff line change
Expand Up @@ -108,9 +108,9 @@ class CBitstreamConverter
bool IsSlice(uint8_t unit_type);
bool BitstreamConvertInitAVC(void *in_extradata, int in_extrasize);
bool BitstreamConvertInitHEVC(void *in_extradata, int in_extrasize);
bool BitstreamConvert(uint8_t* pData, int iSize, uint8_t **poutbuf, int *poutbuf_size);
bool BitstreamConvert(uint8_t* pData, int iSize, uint8_t **poutbuf, uint32_t *poutbuf_size);
static void BitstreamAllocAndCopy(uint8_t** poutbuf,
int* poutbuf_size,
uint32_t* poutbuf_size,
const uint8_t* sps_pps,
uint32_t sps_pps_size,
const uint8_t* in,
Expand Down