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/*
* Vp9 invisible (alt-ref) frame to superframe merge bitstream filter
* Copyright (c) 2016 Ronald S. Bultje <rsbultje@gmail.com>
*
* 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
*/
#include "libavutil/avassert.h"
#include "avcodec.h"
#include "get_bits.h"
#define MAX_CACHE 8
typedef struct VP9BSFContext {
int n_cache;
struct CachedBuf {
uint8_t *data;
int size;
} cache[MAX_CACHE];
} VP9BSFContext;
static void stats(const struct CachedBuf *in, int n_in,
unsigned *_max, unsigned *_sum)
{
int n;
unsigned max = 0, sum = 0;
for (n = 0; n < n_in; n++) {
unsigned sz = in[n].size;
if (sz > max)
max = sz;
sum += sz;
}
*_max = max;
*_sum = sum;
}
static int merge_superframe(const struct CachedBuf *in, int n_in,
uint8_t **poutbuf, int *poutbuf_size)
{
unsigned max, sum, mag, marker, n, sz;
uint8_t *ptr;
stats(in, n_in, &max, &sum);
mag = av_log2(max) >> 3;
marker = 0xC0 + (mag << 3) + (n_in - 1);
sz = *poutbuf_size = sum + 2 + (mag + 1) * n_in;
ptr = *poutbuf = av_malloc(sz);
if (!ptr)
return AVERROR(ENOMEM);
for (n = 0; n < n_in; n++) {
memcpy(ptr, in[n].data, in[n].size);
ptr += in[n].size;
}
#define wloop(mag, wr) \
for (n = 0; n < n_in; n++) { \
wr; \
ptr += mag + 1; \
}
// write superframe with marker 110[mag:2][nframes:3]
*ptr++ = marker;
switch (mag) {
case 0:
wloop(mag, *ptr = in[n].size);
break;
case 1:
wloop(mag, AV_WL16(ptr, in[n].size));
break;
case 2:
wloop(mag, AV_WL24(ptr, in[n].size));
break;
case 3:
wloop(mag, AV_WL32(ptr, in[n].size));
break;
}
*ptr++ = marker;
av_assert0(ptr == &(*poutbuf)[*poutbuf_size]);
return 0;
}
static int vp9_superframe_filter(AVBitStreamFilterContext *bsfc,
AVCodecContext *avctx, const char *args,
uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size,
int keyframe)
{
GetBitContext gb;
VP9BSFContext *ctx = bsfc->priv_data;
int res, invisible, profile, marker, uses_superframe_syntax = 0, n;
marker = buf[buf_size - 1];
if ((marker & 0xe0) == 0xc0) {
int nbytes = 1 + ((marker >> 3) & 0x3);
int n_frames = 1 + (marker & 0x7), idx_sz = 2 + n_frames * nbytes;
uses_superframe_syntax = buf_size >= idx_sz && buf[buf_size - idx_sz] == marker;
}
if ((res = init_get_bits8(&gb, buf, buf_size)) < 0)
return res;
get_bits(&gb, 2); // frame marker
profile = get_bits1(&gb);
profile |= get_bits1(&gb) << 1;
if (profile == 3) profile += get_bits1(&gb);
if (get_bits1(&gb)) {
invisible = 0;
} else {
get_bits1(&gb); // keyframe
invisible = !get_bits1(&gb);
}
if (uses_superframe_syntax && ctx->n_cache > 0) {
av_log(avctx, AV_LOG_ERROR,
"Mixing of superframe syntax and naked VP9 frames not supported");
return AVERROR_INVALIDDATA;
} else if ((!invisible || uses_superframe_syntax) && !ctx->n_cache) {
// passthrough
*poutbuf = (uint8_t *) buf;
*poutbuf_size = buf_size;
return 0;
} else if (ctx->n_cache + 1 >= MAX_CACHE) {
av_log(avctx, AV_LOG_ERROR,
"Too many invisible frames");
return AVERROR_INVALIDDATA;
}
ctx->cache[ctx->n_cache].size = buf_size;
if (invisible && !uses_superframe_syntax) {
ctx->cache[ctx->n_cache].data = av_malloc(buf_size);
if (!ctx->cache[ctx->n_cache].data)
return AVERROR(ENOMEM);
memcpy(ctx->cache[ctx->n_cache++].data, buf, buf_size);
*poutbuf = NULL;
*poutbuf_size = 0;
return 0;
}
av_assert0(ctx->n_cache > 0);
ctx->cache[ctx->n_cache].data = (uint8_t *) buf;
// build superframe
if ((res = merge_superframe(ctx->cache, ctx->n_cache + 1,
poutbuf, poutbuf_size)) < 0)
return res;
for (n = 0; n < ctx->n_cache; n++)
av_freep(&ctx->cache[n].data);
ctx->n_cache = 0;
return 0;
}
static void vp9_superframe_close(AVBitStreamFilterContext *bsfc)
{
VP9BSFContext *ctx = bsfc->priv_data;
int n;
// free cached data
for (n = 0; n < ctx->n_cache; n++)
av_freep(&ctx->cache[n].data);
}
AVBitStreamFilter ff_vp9_superframe_bsf = {
.name = "vp9_superframe",
.priv_data_size = sizeof(VP9BSFContext),
.filter = vp9_superframe_filter,
.close = vp9_superframe_close,
};
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