{"id":2097,"date":"2020-08-20T07:05:10","date_gmt":"2020-08-20T05:05:10","guid":{"rendered":"https:\/\/alax.info\/blog\/?p=2097"},"modified":"2020-09-02T11:53:04","modified_gmt":"2020-09-02T09:53:04","slug":"concurrent-h-264-encoder-sessions-with-amd-gpus","status":"publish","type":"post","link":"https:\/\/alax.info\/blog\/2097","title":{"rendered":"Concurrent H.264 encoder sessions with AMD GPUs"},"content":{"rendered":"\n<p>I was under impression that AMD hardware allows just one video encoding session and prevents from having multiple side by side. This has been the consistent behavior I was seeing and I was always wondering why it had to be that tight.<\/p>\n\n\n\n<p>To my surprise, the actual limitation is higher and, in particular, is sixteen (16!) sessions runnable in parallel. In particular, with the GPU in my dev box&#8230;<\/p>\n\n\n\n<p>The problem has been a <a href=\"https:\/\/github.com\/GPUOpen-LibrariesAndSDKs\/AMF\/issues\/223\">bug<\/a> in AMD driver and\/or AMD AMF runtime, which triggered an exception when in low latency mode. With this bug it is indeed just one session at a time. Even though the bug has been present for literally years, it is good that AMD engineers do respond on github and this results in problem identification, workaround and I hope resolution as well.<\/p>\n\n\n\n<p>The good thing is that just 2+ low latency sessions are not allowed. Multiple regular sessions and zero or one low latency, up to 16 in total, is still fine. That is, a fallback to non low latency session is a possible workaround.<\/p>\n\n\n\n<p>UPDATE: This is a hardware limitation for <a href=\"https:\/\/www.amd.com\/en\/technologies\/polaris\">AMD Polaris Architecture<\/a>: only one process can own low latency hardware queue. Newer GPUs are not affected.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>I was under impression that AMD hardware allows just one video encoding session and prevents from having multiple side by side. This has been the consistent behavior I was seeing and I was always wondering why it had to be that tight. To my surprise, the actual limitation is higher and, in particular, is sixteen&hellip; <\/p>\n<p><a class=\"moretag\" href=\"https:\/\/alax.info\/blog\/2097\">Read the full article<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[553,63,379,486],"class_list":["post-2097","post","type-post","status-publish","format-standard","hentry","category-uncategorized","tag-amd","tag-bug","tag-h-264","tag-video"],"_links":{"self":[{"href":"https:\/\/alax.info\/blog\/wp-json\/wp\/v2\/posts\/2097","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/alax.info\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/alax.info\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/alax.info\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/alax.info\/blog\/wp-json\/wp\/v2\/comments?post=2097"}],"version-history":[{"count":0,"href":"https:\/\/alax.info\/blog\/wp-json\/wp\/v2\/posts\/2097\/revisions"}],"wp:attachment":[{"href":"https:\/\/alax.info\/blog\/wp-json\/wp\/v2\/media?parent=2097"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/alax.info\/blog\/wp-json\/wp\/v2\/categories?post=2097"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/alax.info\/blog\/wp-json\/wp\/v2\/tags?post=2097"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}