PR #24824 opened by AJ Granowski (AJGranowski) URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24824 Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24824.patch
# Summary of changes avcodec/dnxhddec: Increase alpha channel `avpriv_request_sample` verbosity The alpha channel of VC-3 bitstreams are encoded either as DCT-encoded or RLE-encoded alpha blocks. This change differentiates those two when requesting a sample. This is an incremental change towards adding DCT block alpha decoding for the DNxHD codec. Following PRs will work from the VC-3 standard https://pub.smpte.org/doc/st2019-1/20160518-pub/ 8.1.2 Related tickets: https://trac.ffmpeg.org/ticket/3707 >From c9e00480730a0868005c0baa4d1d0f09b6d4a398 Mon Sep 17 00:00:00 2001 From: AJ Granowski <[email protected]> Date: Wed, 30 Sep 2026 15:54:58 -0500 Subject: [PATCH] avcodec/dnxhddec: Increase alpha channel `avpriv_request_sample` verbosity The alpha channel of VC-3 bitstreams are encoded either as DCT-encoded or RLE-encoded alpha blocks. This change differentiates those two when requesting a sample. This is an incremental change towards adding DCT block alpha decoding for the DNxHD codec. Following PRs will work from the VC-3 standard https://pub.smpte.org/doc/st2019-1/20160518-pub/ 8.1.2 Related tickets: https://trac.ffmpeg.org/ticket/3707 --- libavcodec/dnxhddec.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/libavcodec/dnxhddec.c b/libavcodec/dnxhddec.c index 7ec61f9ebd..7ba01351d9 100644 --- a/libavcodec/dnxhddec.c +++ b/libavcodec/dnxhddec.c @@ -208,8 +208,13 @@ static int dnxhd_decode_header(DNXHDContext *ctx, AVFrame *frame, ctx->mbaff = (buf[0x6] >> 5) & 1; ctx->alpha = buf[0x7] & 1; ctx->lla = (buf[0x7] >> 1) & 1; - if (ctx->alpha) - avpriv_request_sample(ctx->avctx, "alpha"); + if (ctx->alpha) { + if (ctx->lla) { + avpriv_request_sample(ctx->avctx, "RLE block alpha decoding"); + } else { + avpriv_request_sample(ctx->avctx, "DCT block alpha decoding"); + } + } ctx->height = AV_RB16(buf + 0x18); ctx->width = AV_RB16(buf + 0x1a); -- 2.52.0 _______________________________________________ ffmpeg-devel mailing list -- [email protected] To unsubscribe send an email to [email protected]
