Composite WOH Documentation

Description

Update documentation to describe fix in JSON configuration to not get:

[swscaler @ 0x17bf320] deprecated pixel format used, make sure you did set range correctly
[swscaler @ 0x17b3dc0] Warning: data is not aligned! This can lead to a speedloss

or Failure of Composite step.

http://superuser.com/questions/728795/new-ffmpeg-swscaler-0xa314080-warning-data-is-not-aligned-this-can-lead.

Activity

Show:
Corné Oosthuizen
January 4, 2017, 2:43 PM

1080 / 16 = 67.5, which is not a whole number, presumably leading to writing 68 items to a buffer with 67 slots, potentially crashing the encoder. Something else might round up to 68, gradually deviating the reported number of processed bits.

According to this thread, the offending code is:

420 if ( (uintptr_t)dst[0]%16 || (uintptr_t)dst[1]%16 || (uintptr_t)dst[2]%16
421 || (uintptr_t)src[0]%16 || (uintptr_t)src[1]%16 || (uintptr_t)src[2]%16
422 || dstStride[0]%16 || dstStride[1]%16 || dstStride[2]%16 || dstStride[3]%16
423 || srcStride[0]%16 || srcStride[1]%16 || srcStride[2]%16 || srcStride[3]%16
424 ) {
425 static int warnedAlready=0;
426 int cpu_flags = av_get_cpu_flags();
427 if (HAVE_MMXEXT && (cpu_flags & AV_CPU_FLAG_SSE2) && !warnedAlready){
428 av_log(c, AV_LOG_WARNING, "Warning: data is not aligned! This can lead to a speedloss\n");
429 warnedAlready=1;
430 }
431 }
1080 % 16 = 8, and the code expects 0, so the size should be a multiple of 16.

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Assignee

Unassigned

Reporter

Corné Oosthuizen