lavc: add a HEVC mp4->annex B bitstream filter

Changelog

@@ -39,6 +39,7 @@ version <next>:
 - rewritten ASF demuxer
 - Go2Meeting decoding support
 - Intel QSV-accelerated MPEG-2 video and HEVC encoding
+- bitstream filter for converting HEVC from MP4 to Annex B
 
 
 version 11:

libavcodec/Makefile

@@ -730,6 +730,7 @@ OBJS-$(CONFIG_AAC_ADTSTOASC_BSF)          += aac_adtstoasc_bsf.o aacadtsdec.o \
 OBJS-$(CONFIG_CHOMP_BSF)                  += chomp_bsf.o
 OBJS-$(CONFIG_DUMP_EXTRADATA_BSF)         += dump_extradata_bsf.o
 OBJS-$(CONFIG_H264_MP4TOANNEXB_BSF)       += h264_mp4toannexb_bsf.o
+OBJS-$(CONFIG_HEVC_MP4TOANNEXB_BSF)       += hevc_mp4toannexb_bsf.o
 OBJS-$(CONFIG_IMX_DUMP_HEADER_BSF)        += imx_dump_header_bsf.o
 OBJS-$(CONFIG_MJPEG2JPEG_BSF)             += mjpeg2jpeg_bsf.o
 OBJS-$(CONFIG_MJPEGA_DUMP_HEADER_BSF)     += mjpega_dump_header_bsf.o

libavcodec/allcodecs.c

@@ -529,6 +529,7 @@ void avcodec_register_all(void)
     REGISTER_BSF(CHOMP,                 chomp);
     REGISTER_BSF(DUMP_EXTRADATA,        dump_extradata);
     REGISTER_BSF(H264_MP4TOANNEXB,      h264_mp4toannexb);
+    REGISTER_BSF(HEVC_MP4TOANNEXB,      hevc_mp4toannexb);
     REGISTER_BSF(IMX_DUMP_HEADER,       imx_dump_header);
     REGISTER_BSF(MJPEG2JPEG,            mjpeg2jpeg);
     REGISTER_BSF(MJPEGA_DUMP_HEADER,    mjpega_dump_header);

libavcodec/hevc_mp4toannexb_bsf.c

+/*
+ * HEVC MP4 to Annex B byte stream format filter
+ * copyright (c) 2015 Anton Khirnov
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <string.h>
+
+#include "libavutil/intreadwrite.h"
+#include "libavutil/mem.h"
+
+#include "avcodec.h"
+#include "bytestream.h"
+#include "hevc.h"
+
+#define MIN_HEVCC_LENGTH 23
+
+typedef struct HEVCBSFContext {
+    uint8_t  length_size;
+    int      extradata_parsed;
+
+    int logged_nonmp4_warning;
+} HEVCBSFContext;
+
+static int hevc_extradata_to_annexb(AVCodecContext *avctx)
+{
+    GetByteContext gb;
+    int length_size, num_arrays, i, j;
+    int ret = 0;
+
+    uint8_t *new_extradata = NULL;
+    size_t   new_extradata_size = 0;;
+
+    bytestream2_init(&gb, avctx->extradata, avctx->extradata_size);
+
+    bytestream2_skip(&gb, 21);
+    length_size = (bytestream2_get_byte(&gb) & 3) + 1;
+    num_arrays  = bytestream2_get_byte(&gb);
+
+    for (i = 0; i < num_arrays; i++) {
+        int type = bytestream2_get_byte(&gb) & 0x3f;
+        int cnt  = bytestream2_get_be16(&gb);
+
+        if (!(type == NAL_VPS || type == NAL_SPS || type == NAL_PPS ||
+              type == NAL_SEI_PREFIX || type == NAL_SEI_SUFFIX)) {
+            av_log(avctx, AV_LOG_ERROR, "Invalid NAL unit type in extradata: %d\n",
+                   type);
+            ret = AVERROR_INVALIDDATA;
+            goto fail;
+        }
+
+        for (j = 0; j < cnt; j++) {
+            int nalu_len = bytestream2_get_be16(&gb);
+
+            if (4 + FF_INPUT_BUFFER_PADDING_SIZE + nalu_len > SIZE_MAX - new_extradata_size) {
+                ret = AVERROR_INVALIDDATA;
+                goto fail;
+            }
+            ret = av_reallocp(&new_extradata, new_extradata_size + nalu_len + 4 + FF_INPUT_BUFFER_PADDING_SIZE);
+            if (ret < 0)
+                goto fail;
+
+            AV_WB32(new_extradata + new_extradata_size, 1); // add the startcode
+            bytestream2_get_buffer(&gb, new_extradata + new_extradata_size + 4, nalu_len);
+            new_extradata_size += 4 + nalu_len;
+            memset(new_extradata + new_extradata_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
+        }
+    }
+
+    av_freep(&avctx->extradata);
+    avctx->extradata      = new_extradata;
+    avctx->extradata_size = new_extradata_size;
+
+    if (!new_extradata_size)
+        av_log(avctx, AV_LOG_WARNING, "No parameter sets in the extradata\n");
+
+    return length_size;
+fail:
+    av_freep(&new_extradata);
+    return ret;
+}
+
+static int hevc_mp4toannexb_filter(AVBitStreamFilterContext *bsfc,
+                                   AVCodecContext *avctx, const char *args,
+                                   uint8_t **poutbuf, int *poutbuf_size,
+                                   const uint8_t *buf, int buf_size,
+                                   int keyframe)
+{
+    HEVCBSFContext *ctx = bsfc->priv_data;
+    GetByteContext gb;
+
+    uint8_t *out = NULL;
+    size_t   out_size = 0;
+    int got_irap = 0;
+    int i, ret = 0;
+
+    if (!ctx->extradata_parsed) {
+        if (avctx->extradata_size < MIN_HEVCC_LENGTH ||
+            AV_RB24(avctx->extradata) == 1           ||
+            AV_RB32(avctx->extradata) == 1) {
+            if (!ctx->logged_nonmp4_warning) {
+                av_log(avctx, AV_LOG_VERBOSE,
+                       "The input looks like it is Annex B already\n");
+                ctx->logged_nonmp4_warning = 1;
+            }
+            *poutbuf      = buf;
+            *poutbuf_size = buf_size;
+            return 0;
+        }
+
+        ret = hevc_extradata_to_annexb(avctx);
+        if (ret < 0)
+            return ret;
+        ctx->length_size      = ret;
+        ctx->extradata_parsed = 1;
+    }
+
+    *poutbuf_size = 0;
+    *poutbuf      = NULL;
+
+    bytestream2_init(&gb, buf, buf_size);
+
+    while (bytestream2_get_bytes_left(&gb)) {
+        uint32_t nalu_size = 0;
+        int      nalu_type;
+        int is_irap, add_extradata, extra_size;
+
+        for (i = 0; i < ctx->length_size; i++)
+            nalu_size = (nalu_size << 8) | bytestream2_get_byte(&gb);
+
+        nalu_type = (bytestream2_peek_byte(&gb) >> 1) & 0x3f;
+
+        /* prepend extradata to IRAP frames */
+        is_irap       = nalu_type >= 16 && nalu_type <= 23;
+        add_extradata = is_irap && !got_irap;
+        extra_size    = add_extradata * avctx->extradata_size;
+        got_irap     |= is_irap;
+
+        if (SIZE_MAX - out_size < 4             ||
+            SIZE_MAX - out_size - 4 < nalu_size ||
+            SIZE_MAX - out_size - 4 - nalu_size < extra_size) {
+            ret = AVERROR_INVALIDDATA;
+            goto fail;
+        }
+
+        ret = av_reallocp(&out, out_size + 4 + nalu_size + extra_size);
+        if (ret < 0)
+            goto fail;
+
+        if (add_extradata)
+            memcpy(out + out_size, avctx->extradata, extra_size);
+        AV_WB32(out + out_size + extra_size, 1);
+        bytestream2_get_buffer(&gb, out + out_size + 4 + extra_size, nalu_size);
+        out_size += 4 + nalu_size + extra_size;
+    }
+
+    *poutbuf      = out;
+    *poutbuf_size = out_size;
+
+    return 1;
+
+fail:
+    av_freep(&out);
+    return ret;
+}
+
+AVBitStreamFilter ff_hevc_mp4toannexb_bsf = {
+    "hevc_mp4toannexb",
+    sizeof(HEVCBSFContext),
+    hevc_mp4toannexb_filter,
+};