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lavc: add an option for exporting cropping information to the caller

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Also, add generic code for handling cropping, so the decoders can export
just the cropping size and not bother with the rest.
pull/202/merge
Anton Khirnov 8 years ago
parent 52627248e4
commit 019ab88a95
6 changed files with 156 additions and 3 deletions
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  1. 4
      doc/APIchanges
  2. 27
      libavcodec/avcodec.h
  3. 117
      libavcodec/decode.c
  4. 6
      libavcodec/internal.h
  5. 1
      libavcodec/options_table.h
  6. 4
      libavcodec/version.h

4
doc/APIchanges
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@ -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/right/top/bottom fields for attaching cropping
information to video frames.

27
libavcodec/avcodec.h
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@ -3112,6 +3112,33 @@ 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. This
* option controls how cropping is handled by libavcodec.
*
* When set to 1 (the default), libavcodec will apply cropping internally.
* I.e. it will modify the output frame width/height fields and 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) so that
* the frames output by the decoder refer only to the cropped area. The
* crop_* fields of the output frames will be zero.
*
* When set to 0, the width/height fields of the output frames will be set
* to the coded dimensions and the crop_* fields will describe the cropping
* rectangle. Applying the cropping is left to the caller.
*
* @warning When hardware acceleration with opaque output frames is used,
* libavcodec is unable to apply cropping from the top/left border.
*
* @note when this option is set to zero, the width/height fields of the
* AVCodecContext and output AVFrames have different meanings. The codec
* context fields store display dimensions (with the coded dimensions in
* coded_width/height), while the frame fields store the coded dimensions
* (with the display dimensions being determined by the crop_* fields).
*/
int apply_cropping;
} AVCodecContext;
/**

117
libavcodec/decode.c
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@ -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 +451,111 @@ 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;
if (desc->flags & (AV_PIX_FMT_FLAG_PAL | AV_PIX_FMT_FLAG_PSEUDOPAL) && i == 1) {
offsets[i] = 0;
break;
}
/* 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 >= INT_MAX - frame->crop_right ||
frame->crop_top >= INT_MAX - frame->crop_bottom ||
(frame->crop_left + frame->crop_right) >= frame->width ||
(frame->crop_top + frame->crop_bottom) >= frame->height) {
av_log(avctx, AV_LOG_WARNING,
"Invalid cropping information set by a decoder: %zu/%zu/%zu/%zu "
"(frame size %dx%d). This is a bug, please report it\n",
frame->crop_left, frame->crop_right, frame->crop_top, frame->crop_bottom,
frame->width, frame->height);
frame->crop_left = 0;
frame->crop_right = 0;
frame->crop_top = 0;
frame->crop_bottom = 0;
return 0;
}
if (!avctx->apply_cropping)
return 0;
desc = av_pix_fmt_desc_get(frame->format);
if (!desc)
return AVERROR_BUG;
/* Apply just the right/bottom cropping for hwaccel formats. Bitstream
* formats cannot be easily handled here either (and corresponding decoders
* should not export any cropping anyway), so do the same for those as well.
* */
if (desc->flags & (AV_PIX_FMT_FLAG_BITSTREAM | AV_PIX_FMT_FLAG_HWACCEL)) {
frame->width -= frame->crop_right;
frame->height -= frame->crop_bottom;
frame->crop_right = 0;
frame->crop_bottom = 0;
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->crop_right);
frame->height -= (frame->crop_top + frame->crop_bottom);
frame->crop_left = 0;
frame->crop_right = 0;
frame->crop_top = 0;
frame->crop_bottom = 0;
return 0;
}
int attribute_align_arg avcodec_receive_frame(AVCodecContext *avctx, AVFrame *frame)
{
AVCodecInternal *avci = avctx->internal;
@ -472,6 +578,14 @@ 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;
@ -1029,7 +1143,8 @@ int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
ret = avctx->get_buffer2(avctx, frame, flags);
end:
if (avctx->codec_type == AVMEDIA_TYPE_VIDEO && !override_dimensions) {
if (avctx->codec_type == AVMEDIA_TYPE_VIDEO && !override_dimensions &&
!(avctx->codec->caps_internal & FF_CODEC_CAP_EXPORTS_CROPPING)) {
frame->width = avctx->width;
frame->height = avctx->height;
}

6
libavcodec/internal.h
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@ -53,6 +53,12 @@
* from the input AVPacket.
*/
#define FF_CODEC_CAP_SETS_PKT_DTS (1 << 2)
/**
* The decoder sets the cropping fields in the output frames manually.
* If this cap is set, the generic code will initialize output frame
* dimensions to coded rather than display values.
*/
#define FF_CODEC_CAP_EXPORTS_CROPPING (1 << 3)
#ifdef DEBUG
# define ff_dlog(ctx, ...) av_log(ctx, AV_LOG_DEBUG, __VA_ARGS__)

1
libavcodec/options_table.h
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@ -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},
};

4
libavcodec/version.h
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@ -28,8 +28,8 @@
#include "libavutil/version.h"
#define LIBAVCODEC_VERSION_MAJOR 57
#define LIBAVCODEC_VERSION_MINOR 30
#define LIBAVCODEC_VERSION_MICRO 4
#define LIBAVCODEC_VERSION_MINOR 31
#define LIBAVCODEC_VERSION_MICRO 0
#define LIBAVCODEC_VERSION_INT AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
LIBAVCODEC_VERSION_MINOR, \

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