[FFmpeg-devel] [PATCH] avcodec/dxvenc: Use proper alignment, write endian-independent output

[Andreas Rheinhardt]

Sean McGovern:
> Hi,
> 
> On Mon, Feb 26, 2024 at 6:48 PM Andreas Rheinhardt
> <andreas.rheinhardt at outlook.com> wrote:
>>
>> Fixes the dxv3enc-dxt1 FATE test with UBSan.
>>
>> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
>> ---
>> I have not actually tested whether the output is actually wrong
>> on BE systems. Would be nice if someone could.
>>
>>  libavcodec/dxvenc.c | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/libavcodec/dxvenc.c b/libavcodec/dxvenc.c
>> index 1ce2b1d014..3f28fb696a 100644
>> --- a/libavcodec/dxvenc.c
>> +++ b/libavcodec/dxvenc.c
>> @@ -149,7 +149,7 @@ typedef struct DXVEncContext {
>>          } else {                                                              \
>>              op = 0;                                                           \
>>          }                                                                     \
>> -        *value |= (op << (state * 2));                                        \
>> +        AV_WL32(value, AV_RL32(value) | (op << (state * 2)));                 \
>>          state++;                                                              \
>>      } while (0)
>>
>> @@ -157,7 +157,7 @@ static int dxv_compress_dxt1(AVCodecContext *avctx)
>>  {
>>      DXVEncContext *ctx = avctx->priv_data;
>>      PutByteContext *pbc = &ctx->pbc;
>> -    uint32_t *value;
>> +    void *value;
>>      uint32_t color, lut, idx, color_idx, lut_idx, prev_pos, state = 16, pos = 2, op = 0;
>>
>>      ht_init(ctx->color_lookback_ht);
> 
> Confirming that this does fix the failing test on a big-endian PowerPC
> + Altivec virtual machine.
> 

Thanks for testing, applied the patch with James' suggested modification.

- Andreas