Also, add generic code for handling cropping, so the decoders can export just the cropping size and not bother with the rest. --- doc/APIchanges | 4 ++ libavcodec/avcodec.h | 26 +++++++++++++ libavcodec/decode.c | 96 ++++++++++++++++++++++++++++++++++++++++++++++ libavcodec/options_table.h | 1 + libavcodec/version.h | 2 +- 5 files changed, 128 insertions(+), 1 deletion(-)
diff --git a/doc/APIchanges b/doc/APIchanges index ca95308..011e4ab 100644 --- a/doc/APIchanges +++ b/doc/APIchanges @@ -13,6 +13,10 @@ libavutil: 2015-08-28 API changes, most recent first: +2016-xx-xx - xxxxxxx - lavc 57.31.0 - avcodec.h + Add AVCodecContext.apply_cropping to control whether cropping + is handled by libavcodec or the caller. + 2016-xx-xx - xxxxxxx - lavu 55.30.0 - frame.h Add AVFrame.crop_left/crop_top fields for attaching cropping information to video frames. diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h index 0997141..b02b394 100644 --- a/libavcodec/avcodec.h +++ b/libavcodec/avcodec.h @@ -3112,6 +3112,32 @@ typedef struct AVCodecContext { * This field should be set before avcodec_open2() is called. */ AVBufferRef *hw_frames_ctx; + + /** + * Video decoding only. Certain video codecs support cropping, meaning that + * only a sub-rectangle of the decoded frame is intended for display. + * Cropping from the right/bottom amounts to simply decreasing the + * width/height of the output frames and is always done internally by + * libavcodec. However cropping from the left/top border requires modifying + * the data pointers and cannot be handled by libavcodec in certain cases + * (e.g. opaque frames with hardware acceleration or where such an offset + * would break data alignment). + * + * This option controls how left/top cropping is handled by libavcodec. + * + * When set to 1 (the default), libavcodec will offset the data pointers + * (only by as much as possible while preserving alignment, or by the full + * amount if the AV_CODEC_FLAG_UNALIGNED flag is set). The left/top_offset + * fields of the output frames will be zero. + * + * When set to 0, libavcodec will set the left/top_offset fields on the + * output frames and leave applying the left/top cropping to the caller. + * + * When hardware acceleration with opaque output frames is used, the actual + * value of this option is disregarded and libavcodec behaves as if it was + * set to 0. + */ + int apply_cropping; } AVCodecContext; /** diff --git a/libavcodec/decode.c b/libavcodec/decode.c index 0fd41ab..76fb0ff 100644 --- a/libavcodec/decode.c +++ b/libavcodec/decode.c @@ -29,6 +29,7 @@ #include "libavutil/frame.h" #include "libavutil/hwcontext.h" #include "libavutil/imgutils.h" +#include "libavutil/intmath.h" #include "avcodec.h" #include "bytestream.h" @@ -450,6 +451,93 @@ int attribute_align_arg avcodec_send_packet(AVCodecContext *avctx, const AVPacke return 0; } +static int calc_cropping_offsets(size_t offsets[4], const AVFrame *frame, + const AVPixFmtDescriptor *desc) +{ + int i, j; + + for (i = 0; frame->data[i]; i++) { + const AVComponentDescriptor *comp = NULL; + int shift_x = (i == 1 || i == 2) ? desc->log2_chroma_w : 0; + int shift_y = (i == 1 || i == 2) ? desc->log2_chroma_h : 0; + + /* find any component descriptor for this plane */ + for (j = 0; j < desc->nb_components; j++) { + if (desc->comp[j].plane == i) { + comp = &desc->comp[j]; + break; + } + } + if (!comp) + return AVERROR_BUG; + + offsets[i] = (frame->crop_top >> shift_y) * frame->linesize[i] + + (frame->crop_left >> shift_x) * comp->step; + } + + return 0; +} + +static int apply_cropping(AVCodecContext *avctx, AVFrame *frame) +{ + const AVPixFmtDescriptor *desc; + size_t offsets[4]; + int i; + + /* make sure we are noisy about decoders returning invalid cropping data */ + if (frame->crop_left >= frame->width || frame->crop_top >= frame->height) { + av_log(avctx, AV_LOG_WARNING, + "Invalid cropping information set by a decoder: %zu/%zu " + "(frame size %dx%d). This is a bug, please report it\n", + frame->crop_left, frame->crop_top, frame->width, frame->height); + frame->crop_left = 0; + frame->crop_top = 0; + return 0; + } + + if (!avctx->apply_cropping) + return 0; + + desc = av_pix_fmt_desc_get(frame->format); + if (!desc) + return AVERROR_BUG; + + /* Do nothing for hwaccel formats. + * Bitstream formats cannot be easily handled here either (and corresponding + * decoders should not export any cropping anyway), so also do nothing for + * those. */ + if (desc->flags & (AV_PIX_FMT_FLAG_BITSTREAM | AV_PIX_FMT_FLAG_HWACCEL)) + return 0; + + /* calculate the offsets for each plane */ + calc_cropping_offsets(offsets, frame, desc); + + /* adjust the offsets to avoid breaking alignment */ + if (!(avctx->flags & AV_CODEC_FLAG_UNALIGNED)) { + int min_log2_align = INT_MAX; + + for (i = 0; frame->data[i]; i++) { + int log2_align = offsets[i] ? av_ctz(offsets[i]) : INT_MAX; + min_log2_align = FFMIN(log2_align, min_log2_align); + } + + if (min_log2_align < 5) { + frame->crop_left &= ~((1 << min_log2_align) - 1); + calc_cropping_offsets(offsets, frame, desc); + } + } + + for (i = 0; frame->data[i]; i++) + frame->data[i] += offsets[i]; + + frame->width -= frame->crop_left; + frame->height -= frame->crop_top; + frame->crop_left = 0; + frame->crop_top = 0; + + return 0; +} + int attribute_align_arg avcodec_receive_frame(AVCodecContext *avctx, AVFrame *frame) { AVCodecInternal *avci = avctx->internal; @@ -472,6 +560,14 @@ int attribute_align_arg avcodec_receive_frame(AVCodecContext *avctx, AVFrame *fr return ret; } + if (avctx->codec_type == AVMEDIA_TYPE_VIDEO) { + ret = apply_cropping(avctx, frame); + if (ret < 0) { + av_frame_unref(frame); + return ret; + } + } + avctx->frame_number++; return 0; diff --git a/libavcodec/options_table.h b/libavcodec/options_table.h index 4deb223..3ac53fb 100644 --- a/libavcodec/options_table.h +++ b/libavcodec/options_table.h @@ -531,6 +531,7 @@ static const AVOption avcodec_options[] = { #if FF_API_SIDEDATA_ONLY_PKT {"side_data_only_packets", NULL, OFFSET(side_data_only_packets), AV_OPT_TYPE_INT, { .i64 = 1 }, 0, 1, A|V|E }, #endif +{"apply_cropping", NULL, OFFSET(apply_cropping), AV_OPT_TYPE_INT, { .i64 = 1 }, 0, 1, V | D }, {NULL}, }; diff --git a/libavcodec/version.h b/libavcodec/version.h index adab9b4..df0c01f 100644 --- a/libavcodec/version.h +++ b/libavcodec/version.h @@ -28,7 +28,7 @@ #include "libavutil/version.h" #define LIBAVCODEC_VERSION_MAJOR 57 -#define LIBAVCODEC_VERSION_MINOR 30 +#define LIBAVCODEC_VERSION_MINOR 31 #define LIBAVCODEC_VERSION_MICRO 0 #define LIBAVCODEC_VERSION_INT AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \ -- 2.0.0 _______________________________________________ libav-devel mailing list libav-devel@libav.org https://lists.libav.org/mailman/listinfo/libav-devel