From: Christophe Gisquet <[email protected]> This bit is 1 in some samples, and seems to coincide with interlaced mbs and CID1260. 2008 specs do not know about it, and maintain qscale is 11 bits. This looks oversized, but may help larger bitdepths.
Currently, it leads to an obviously incorrect qscale value, meaning its syntax is shifted by 1. However, reading 11 bits also leads to obviously incorrect decoding: qscale seems to be 10 bits. However, as most profiles still have 11bits qscale, the feature is restricted to the CID1260 profile. The encoder writes 12 bits of syntax, last and first bits always 0, which is now somewhat inconsistent with the decoder, but ends up with the same effect (progressive + reserved bit). Signed-off-by: Vittorio Giovara <[email protected]> --- libavcodec/dnxhddec.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/libavcodec/dnxhddec.c b/libavcodec/dnxhddec.c index 1c11dab..a7c9147 100644 --- a/libavcodec/dnxhddec.c +++ b/libavcodec/dnxhddec.c @@ -324,8 +324,14 @@ static int dnxhd_decode_macroblock(DNXHDContext *ctx, AVFrame *frame, uint8_t *dest_y, *dest_u, *dest_v; int dct_y_offset, dct_x_offset; int qscale, i; + int interlaced_mb = 0; - qscale = get_bits(&ctx->gb, 11); + if (ctx->cid_table->cid == 1260) { + interlaced_mb = get_bits1(&ctx->gb); + qscale = get_bits(&ctx->gb, 10); + } else { + qscale = get_bits(&ctx->gb, 11); + } skip_bits1(&ctx->gb); for (i = 0; i < 8; i++) { @@ -353,8 +359,12 @@ static int dnxhd_decode_macroblock(DNXHDContext *ctx, AVFrame *frame, dest_u += frame->linesize[1]; dest_v += frame->linesize[2]; } + if (interlaced_mb) { + dct_linesize_luma <<= 1; + dct_linesize_chroma <<= 1; + } - dct_y_offset = dct_linesize_luma << 3; + dct_y_offset = interlaced_mb ? frame->linesize[0] : (dct_linesize_luma << 3); dct_x_offset = 8 << shift1; if (!ctx->is_444) { ctx->idsp.idct_put(dest_y, dct_linesize_luma, ctx->blocks[0]); @@ -363,7 +373,7 @@ static int dnxhd_decode_macroblock(DNXHDContext *ctx, AVFrame *frame, ctx->idsp.idct_put(dest_y + dct_y_offset + dct_x_offset, dct_linesize_luma, ctx->blocks[5]); if (!(ctx->avctx->flags & AV_CODEC_FLAG_GRAY)) { - dct_y_offset = dct_linesize_chroma << 3; + dct_y_offset = interlaced_mb ? frame->linesize[1] : (dct_linesize_chroma << 3); ctx->idsp.idct_put(dest_u, dct_linesize_chroma, ctx->blocks[2]); ctx->idsp.idct_put(dest_v, dct_linesize_chroma, ctx->blocks[3]); ctx->idsp.idct_put(dest_u + dct_y_offset, dct_linesize_chroma, ctx->blocks[6]); @@ -376,7 +386,7 @@ static int dnxhd_decode_macroblock(DNXHDContext *ctx, AVFrame *frame, ctx->idsp.idct_put(dest_y + dct_y_offset + dct_x_offset, dct_linesize_luma, ctx->blocks[7]); if (!(ctx->avctx->flags & AV_CODEC_FLAG_GRAY)) { - dct_y_offset = dct_linesize_chroma << 3; + dct_y_offset = interlaced_mb ? frame->linesize[1] : (dct_linesize_chroma << 3); ctx->idsp.idct_put(dest_u, dct_linesize_chroma, ctx->blocks[2]); ctx->idsp.idct_put(dest_u + dct_x_offset, dct_linesize_chroma, ctx->blocks[3]); ctx->idsp.idct_put(dest_u + dct_y_offset, dct_linesize_chroma, ctx->blocks[8]); -- 1.9.5 (Apple Git-50.3) _______________________________________________ libav-devel mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-devel
