lavc: add a OpenEXR decoder

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

1 files changed, 485 insertions, 0 deletions

diff --git a/libavcodec/exr.c b/libavcodec/exr.c
new file mode 100644
index 0000000000..d18e1f0d14
--- /dev/null
+++ b/libavcodec/exr.c
@@ -0,0 +1,485 @@
+/*
+ * OpenEXR (.exr) image decoder
+ * Copyright (c) 2009 Jimmy Christensen
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file libavcodec/exr.c
+ * OpenEXR decoder
+ * @author Jimmy Christensen
+ *
+ * For more information on the OpenEXR format, visit:
+ *  http://openexr.com/
+ *
+ * exr_flt2uint() and exr_halflt2uint() is credited to  Reimar Döffinger
+ */
+
+#include "avcodec.h"
+#include "bytestream.h"
+#include "libavutil/imgutils.h"
+
+enum ExrCompr {
+    EXR_RAW   = 0,
+    EXR_RLE   = 1,
+    EXR_ZIP1  = 2,
+    EXR_ZIP16 = 3,
+    EXR_PIZ   = 4,
+    EXR_B44   = 6
+};
+
+typedef struct EXRContext {
+    AVFrame picture;
+    int compr;
+    int bits_per_color_id;
+    int8_t channel_offsets[3]; // 0 = red, 1 = green and 2 = blue
+} EXRContext;
+
+/**
+ * Converts from 32-bit float as uint32_t to uint16_t
+ *
+ * @param v 32-bit float
+ * @return normalized 16-bit unsigned int
+ */
+static inline uint16_t exr_flt2uint(uint32_t v)
+{
+    unsigned int exp = v >> 23;
+    // "HACK": negative values result in exp<  0, so clipping them to 0
+    // is also handled by this condition, avoids explicit check for sign bit.
+    if (exp<= 127 + 7 - 24) // we would shift out all bits anyway
+        return 0;
+    if (exp >= 127)
+        return 0xffff;
+    v &= 0x007fffff;
+    return (v + (1 << 23)) >> (127 + 7 - exp);
+}
+
+/**
+ * Converts from 16-bit float as uint16_t to uint16_t
+ *
+ * @param v 16-bit float
+ * @return normalized 16-bit unsigned int
+ */
+static inline uint16_t exr_halflt2uint(uint16_t v)
+{
+    int exp = v >> 10;
+    if (v & 0x8000)
+        return 0;
+    if (!exp)
+        return (v >> 9) & 1;
+    if (exp >= 15)
+        return 0xffff;
+    v <<= 6;
+    return (v + (1 << 16)) >> (15 - exp);
+}
+
+/**
+ * Gets the size of the header variable
+ *
+ * @param **buf the current pointer location in the header where
+ * the variable data starts
+ * @param *buf_end pointer location of the end of the buffer
+ * @return size of variable data
+ */
+static unsigned int get_header_variable_length(const uint8_t **buf,
+                                               const uint8_t *buf_end)
+{
+    unsigned int variable_buffer_data_size = bytestream_get_le32(buf);
+    if (variable_buffer_data_size >= buf_end - *buf)
+        return 0;
+    return variable_buffer_data_size;
+}
+
+/**
+ * Checks if the variable name corresponds with it's data type
+ *
+ * @param *avctx the AVCodecContext
+ * @param **buf the current pointer location in the header where
+ * the variable name starts
+ * @param *buf_end pointer location of the end of the buffer
+ * @param *value_name name of the varible to check
+ * @param *value_type type of the varible to check
+ * @param minimum_length minimum length of the variable data
+ * @param variable_buffer_data_size variable length read from the header
+ * after it's checked
+ * @return zero if variable is invalid and 1 if good
+ */
+static unsigned int check_header_variable(AVCodecContext *avctx,
+                                              const uint8_t **buf,
+                                              const uint8_t *buf_end,
+                                              const char *value_name,
+                                              const char *value_type,
+                                              unsigned int minimum_length,
+                                              unsigned int *variable_buffer_data_size)
+{
+    if (buf_end - *buf >= minimum_length && !strcmp(*buf, value_name)) {
+        *buf += strlen(value_name)+1;
+        if (!strcmp(*buf, value_type)) {
+            *buf += strlen(value_type)+1;
+            *variable_buffer_data_size = get_header_variable_length(buf, buf_end);
+            if (!*variable_buffer_data_size)
+                av_log(avctx, AVERROR_INVALIDDATA, "Incomplete header\n");
+            return 1;
+        }
+        *buf -= strlen(value_name)+1;
+        av_log(avctx, AV_LOG_WARNING, "Unknown data type for header variable %s\n", value_name);
+    }
+    return 0;
+}
+
+static int decode_frame(AVCodecContext *avctx,
+                        void *data,
+                        int *data_size,
+                        AVPacket *avpkt)
+{
+    const uint8_t *buf      = avpkt->data;
+    unsigned int   buf_size = avpkt->size;
+    const uint8_t *buf_end  = buf + buf_size;
+
+    EXRContext *const s = avctx->priv_data;
+    AVFrame *picture  = data;
+    AVFrame *const p = &s->picture;
+    uint8_t *ptr;
+
+    int x, y, stride, magic_number, version_flag;
+    int w = 0;
+    int h = 0;
+    unsigned int xmin   = ~0;
+    unsigned int xmax   = ~0;
+    unsigned int ymin   = ~0;
+    unsigned int ymax   = ~0;
+    unsigned int xdelta = ~0;
+
+    unsigned int current_channel_offset = 0;
+
+    s->channel_offsets[0] = -1;
+    s->channel_offsets[1] = -1;
+    s->channel_offsets[2] = -1;
+    s->bits_per_color_id = -1;
+
+    magic_number = bytestream_get_le32(&buf);
+    if (magic_number != 20000630) { // As per documentation of OpenEXR it's supposed to be int 20000630 little-endian
+        av_log(avctx, AVERROR_INVALIDDATA, "Wrong magic number %d\n", magic_number);
+        return -1;
+    }
+
+    version_flag = bytestream_get_le32(&buf);
+    if ((version_flag & 0x200) == 0x200) {
+        av_log(avctx, AVERROR_NOFMT, "Tile based images are not supported\n");
+        return -1;
+    }
+
+    if (buf_end - buf < 10) {
+        av_log(avctx, AVERROR_INVALIDDATA, "Too short header to parse\n");
+        return -1;
+    }
+
+    // Parse the header
+    while (buf[0] != 0x0) {
+        unsigned int variable_buffer_data_size;
+        // Process the channel list
+        if (check_header_variable(avctx, &buf, buf_end, "channels", "chlist", 38, &variable_buffer_data_size)) {
+            const uint8_t *channel_list_end;
+            if (!variable_buffer_data_size)
+                return -1;
+
+            channel_list_end = buf + variable_buffer_data_size + 4;
+            while (channel_list_end - buf >= 19) {
+                int current_bits_per_color_id = -1;
+                int channel_index = -1;
+
+                if (!strcmp(buf, "R"))
+                    channel_index = 0;
+                if (!strcmp(buf, "G"))
+                    channel_index = 1;
+                if (!strcmp(buf, "B"))
+                    channel_index = 2;
+
+                while (bytestream_get_byte(&buf) && buf < channel_list_end)
+                    continue; /* skip */
+
+                if (channel_list_end - * &buf < 4) {
+                    av_log(avctx, AVERROR_INVALIDDATA, "Incomplete header\n");
+                    return -1;
+                }
+
+                current_bits_per_color_id = bytestream_get_le32(&buf);
+                if (current_bits_per_color_id > 2) {
+                    av_log(avctx, AVERROR_NOFMT, "Unknown color format\n");
+                    return -1;
+                }
+
+                if (channel_index >= 0) {
+                    if (s->bits_per_color_id != -1 && s->bits_per_color_id != current_bits_per_color_id) {
+                        av_log(avctx, AVERROR_NOFMT, "RGB channels not of the same depth\n");
+                        return -1;
+                    }
+                    s->bits_per_color_id  = current_bits_per_color_id;
+                    s->channel_offsets[channel_index] = current_channel_offset;
+                }
+
+                current_channel_offset += 1 << current_bits_per_color_id;
+                buf += 12;
+            }
+
+            /* Check if all channels are set with an offset or if the channels
+             * are causing an overflow  */
+
+            if (FFMIN3(s->channel_offsets[0],
+                       s->channel_offsets[1],
+                       s->channel_offsets[2]) < 0) {
+                if (s->channel_offsets[0] < 0)
+                    av_log(avctx, AVERROR_NOFMT, "Missing red channel\n");
+                if (s->channel_offsets[1] < 0)
+                    av_log(avctx, AVERROR_NOFMT, "Missing green channel\n");
+                if (s->channel_offsets[2] < 0)
+                    av_log(avctx, AVERROR_NOFMT, "Missing blue channel\n");
+                return -1;
+            }
+
+            buf = channel_list_end;
+            continue;
+        }
+
+        // Process the dataWindow variable
+        if (check_header_variable(avctx, &buf, buf_end, "dataWindow", "box2i", 31, &variable_buffer_data_size)) {
+            if (!variable_buffer_data_size)
+                return -1;
+
+            xmin = AV_RL32(buf);
+            ymin = AV_RL32(buf + 4);
+            xmax = AV_RL32(buf + 8);
+            ymax = AV_RL32(buf + 12);
+            xdelta = (xmax-xmin) + 1;
+
+            buf += variable_buffer_data_size;
+            continue;
+        }
+
+        // Process the displayWindow variable
+        if (check_header_variable(avctx, &buf, buf_end, "displayWindow", "box2i", 34, &variable_buffer_data_size)) {
+            if (!variable_buffer_data_size)
+                return -1;
+
+            w = AV_RL32(buf + 8) + 1;
+            h = AV_RL32(buf + 12) + 1;
+
+            buf += variable_buffer_data_size;
+            continue;
+        }
+
+        // Process the lineOrder variable
+        if (check_header_variable(avctx, &buf, buf_end, "lineOrder", "lineOrder", 25, &variable_buffer_data_size)) {
+            if (!variable_buffer_data_size)
+                return -1;
+
+            if (*buf) {
+                av_log(avctx, AVERROR_NOFMT, "Doesn't support this line order : %d\n", *buf);
+                return -1;
+            }
+
+            buf += variable_buffer_data_size;
+            continue;
+        }
+
+        // Process the compression variable
+        if (check_header_variable(avctx, &buf, buf_end, "compression", "compression", 29, &variable_buffer_data_size)) {
+            if (!variable_buffer_data_size)
+                return -1;
+
+            switch (*buf) {
+            case EXR_RAW:
+                s->compr = *buf;
+                break;
+            case EXR_RLE:
+            case EXR_ZIP1:
+            case EXR_ZIP16:
+            case EXR_PIZ:
+            case EXR_B44:
+            default:
+                av_log(avctx, AVERROR_NOFMT, "This type of compression is not supported\n");
+                return -1;
+            }
+
+            buf += variable_buffer_data_size;
+            continue;
+        }
+
+        // Check if there is enough bytes for a header
+        if (buf_end - buf <= 9) {
+            av_log(avctx, AVERROR_INVALIDDATA, "Incomplete header\n");
+            return -1;
+        }
+
+        // Process unknown variables
+        for (int i = 0; i < 2; i++) {
+            // Skip variable name/type
+            while (buf++ < buf_end)
+                if (buf[0] == 0x0)
+                    break;
+        }
+        buf++;
+        // Skip variable length
+        if (buf_end - buf >= 5) {
+            variable_buffer_data_size = get_header_variable_length(&buf, buf_end);
+            if (!variable_buffer_data_size) {
+                av_log(avctx, AVERROR_INVALIDDATA, "Incomplete header\n");
+                return -1;
+            }
+            buf += variable_buffer_data_size;
+        }
+    }
+
+    if (buf >= buf_end) {
+        av_log(avctx, AVERROR_EOF, "Incomplete file\n");
+        return -1;
+    }
+    buf++;
+
+    switch (s->bits_per_color_id) {
+    case 2: // 32-bit
+    case 1: // 16-bit
+        avctx->pix_fmt = PIX_FMT_RGB48;
+        break;
+    // 8-bit
+    case 0:
+        av_log_missing_feature(avctx, "8-bit OpenEXR", 1);
+        return -1;
+    default:
+        av_log(avctx, AVERROR_NOFMT, "Unknown color format : %d\n", s->bits_per_color_id);
+        return -1;
+    }
+
+    if (s->picture.data[0])
+        avctx->release_buffer(avctx, &s->picture);
+    if (av_image_check_size(w, h, 0, avctx))
+        return -1;
+
+    // Verify the xmin, xmax, ymin, ymax and xdelta before setting the actual image size
+    if (xmin > w || xmin == ~0 ||
+        xmax > w || xmax == ~0 ||
+        ymin > h || ymin == ~0 ||
+        ymax > h || ymax == ~0 ||
+        xdelta == ~0) {
+        av_log(avctx, AVERROR_INVALIDDATA, "Wrong sizing or missing size information\n");
+        return -1;
+    }
+
+    if (w != avctx->width || h != avctx->height) {
+        avcodec_set_dimensions(avctx, w, h);
+    }
+
+    if (avctx->get_buffer(avctx, p) < 0) {
+        av_log(avctx, AVERROR_IO, "get_buffer() failed\n");
+        return -1;
+    }
+
+    ptr    = p->data[0];
+    stride = p->linesize[0];
+
+    // Zero out the start if ymin is not 0
+    for (y = 0; y < ymin; y++) {
+        memset(ptr, 0, avctx->width * 6);
+        ptr += stride;
+    }
+
+    // Process the actual lines
+    for (y = ymin; y <= ymax; y++) {
+        uint16_t *ptr_x = (uint16_t *)ptr;
+        if (buf_end - buf > 8) {
+            /* Read the lineoffset from the line offset table and add 8 bytes
+               to skip the coordinates and data size fields */
+            const uint64_t line_offset = bytestream_get_le64(&buf) + 8;
+            // Check if the buffer has the required bytes needed from the offset
+            if (line_offset > avpkt->size - xdelta * current_channel_offset) {
+                // Line offset is probably wrong and not inside the buffer
+                av_log(avctx, AV_LOG_WARNING, "Line offset for line %d is out of reach setting it to black\n", y);
+                memset(ptr_x, 0, avctx->width * 6);
+            } else {
+                const uint8_t *red_channel_buffer   = avpkt->data + line_offset + xdelta * s->channel_offsets[0];
+                const uint8_t *green_channel_buffer = avpkt->data + line_offset + xdelta * s->channel_offsets[1];
+                const uint8_t *blue_channel_buffer  = avpkt->data + line_offset + xdelta * s->channel_offsets[2];
+
+                // Zero out the start if xmin is not 0
+                memset(ptr_x, 0, xmin * 6);
+                ptr_x += xmin * 3;
+                if (s->bits_per_color_id == 2) {
+                    // 32-bit
+                    for (x = 0; x < xdelta; x++) {
+                        *ptr_x++ = exr_flt2uint(bytestream_get_le32(&red_channel_buffer));
+                        *ptr_x++ = exr_flt2uint(bytestream_get_le32(&green_channel_buffer));
+                        *ptr_x++ = exr_flt2uint(bytestream_get_le32(&blue_channel_buffer));
+                    }
+                } else {
+                    // 16-bit
+                    for (x = 0; x < xdelta; x++) {
+                        *ptr_x++ = exr_halflt2uint(bytestream_get_le16(&red_channel_buffer));
+                        *ptr_x++ = exr_halflt2uint(bytestream_get_le16(&green_channel_buffer));
+                        *ptr_x++ = exr_halflt2uint(bytestream_get_le16(&blue_channel_buffer));
+                    }
+                }
+
+                // Zero out the end if xmax+1 is not w
+                memset(ptr_x, 0, (avctx->width - (xmax + 1)) * 6);
+                ptr_x += (avctx->width - (xmax + 1)) * 3;
+
+            }
+            // Move to next line
+            ptr += stride;
+        }
+    }
+
+    // Zero out the end if ymax+1 is not h
+    for (y = ymax; y < avctx->height; y++) {
+        memset(ptr, 0, avctx->width * 6);
+        ptr += stride;
+    }
+
+    *picture   = s->picture;
+    *data_size = sizeof(AVPicture);
+
+    return buf_size;
+}
+
+static av_cold int decode_init(AVCodecContext *avctx)
+{
+    EXRContext *s = avctx->priv_data;
+    avcodec_get_frame_defaults(&s->picture);
+    avctx->coded_frame = &s->picture;
+    return 0;
+}
+
+static av_cold int decode_end(AVCodecContext *avctx)
+{
+    EXRContext *s = avctx->priv_data;
+    if (s->picture.data[0])
+        avctx->release_buffer(avctx, &s->picture);
+
+    return 0;
+}
+
+AVCodec ff_exr_decoder = {
+    .name               = "exr",
+    .type               = AVMEDIA_TYPE_VIDEO,
+    .id                 = CODEC_ID_EXR,
+    .priv_data_size     = sizeof(EXRContext),
+    .init               = decode_init,
+    .close              = decode_end,
+    .decode             = decode_frame,
+    .long_name          = NULL_IF_CONFIG_SMALL("OpenEXR image"),
+};