[FFmpeg-devel] [PATCH v3 4/4] lavc, doc: add libuavs3d video decoder wrapper
Mark Thompson
sw at jkqxz.net
Wed Aug 12 01:18:46 EEST 2020
On 05/08/2020 17:18, hwrenx at 126.com wrote:
> From: hwren <hwrenx at 126.com>
>
> Signed-off-by: hbj <hanbj at pku.edu.cn>
> Signed-off-by: hwren <hwrenx at 126.com>
> ---
> Changelog | 1 +
> configure | 4 +
> doc/decoders.texi | 21 +++
> doc/general.texi | 8 ++
> libavcodec/Makefile | 1 +
> libavcodec/allcodecs.c | 1 +
> libavcodec/libuavs3d.c | 283 +++++++++++++++++++++++++++++++++++++++++
> 7 files changed, 319 insertions(+)
> create mode 100644 libavcodec/libuavs3d.c
>
> ...
> diff --git a/libavcodec/libuavs3d.c b/libavcodec/libuavs3d.c
> new file mode 100644
> index 0000000000..c0d89cd1ce
> --- /dev/null
> +++ b/libavcodec/libuavs3d.c
> @@ -0,0 +1,283 @@
> +/*
> + * RAW AVS3-P2/IEEE1857.10 video demuxer
> + * Copyright (c) 2020 Zhenyu Wang <wangzhenyu at pkusz.edu.cn>
> + * Bingjie Han <hanbj at pkusz.edu.cn>
> + * Huiwen Ren <hwrenx at 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 "libavutil/avutil.h"
> +#include "libavutil/common.h"
> +#include "libavutil/imgutils.h"
> +#include "libavutil/opt.h"
> +#include "avcodec.h"
> +#include "internal.h"
> +#include "uavs3d.h"
> +
> +#define UAVS3D_MAX_FRAME_THREADS 48
This restriction seems weird. Is it reflecting some intrinsic property of the codec, or might it change in future?
> +
> +static const int color_primaries_tab[10] = {
> + AVCOL_PRI_RESERVED0 , // 0
> + AVCOL_PRI_BT709 , // 1
> + AVCOL_PRI_UNSPECIFIED , // 2
> + AVCOL_PRI_RESERVED , // 3
> + AVCOL_PRI_BT470M , // 4
> + AVCOL_PRI_BT470BG , // 5
> + AVCOL_PRI_SMPTE170M , // 6
> + AVCOL_PRI_SMPTE240M , // 7
> + AVCOL_PRI_FILM , // 8
> + AVCOL_PRI_BT2020 // 9
> +};
> +
> +static const int color_transfer_tab[15] = {
> + AVCOL_TRC_RESERVED0 , // 0
> + AVCOL_TRC_BT709 , // 1
> + AVCOL_TRC_UNSPECIFIED , // 2
> + AVCOL_TRC_RESERVED , // 3
> + AVCOL_TRC_GAMMA22 , // 4
> + AVCOL_TRC_GAMMA28 , // 5
> + AVCOL_TRC_SMPTE170M , // 6
> + AVCOL_TRC_SMPTE240M , // 7
> + AVCOL_TRC_LINEAR , // 8
> + AVCOL_TRC_LOG , // 9
> + AVCOL_TRC_LOG_SQRT , // 10
> + AVCOL_TRC_BT2020_12 , // 11
> + AVCOL_TRC_SMPTE2084 , // 12
> + AVCOL_TRC_UNSPECIFIED , // 13
> + AVCOL_TRC_ARIB_STD_B67 // 14
> +};
> +
> +static const int color_matrix_tab[12] = {
> + AVCOL_SPC_RESERVED , // 0
> + AVCOL_SPC_BT709 , // 1
> + AVCOL_SPC_UNSPECIFIED , // 2
> + AVCOL_SPC_RESERVED , // 3
> + AVCOL_SPC_FCC , // 4
> + AVCOL_SPC_BT470BG , // 5
> + AVCOL_SPC_SMPTE170M , // 6
> + AVCOL_SPC_SMPTE240M , // 7
> + AVCOL_SPC_BT2020_NCL , // 8
> + AVCOL_SPC_BT2020_CL , // 9
> + AVCOL_SPC_UNSPECIFIED , // 10
> + AVCOL_SPC_UNSPECIFIED // 11
> +};
These tables aren't used anywhere.
> +
> +static const enum AVPictureType IMGTYPE[8] = {
This name is doesn't conform to the usual naming convention. uavs3_frame_types[], maybe?
> + AV_PICTURE_TYPE_NONE,
> + AV_PICTURE_TYPE_I,
> + AV_PICTURE_TYPE_P,
> + AV_PICTURE_TYPE_B
> +};
What do the other four values in the table mean?
> +
> +typedef struct UAVS3DContext {
> + AVCodecContext *avctx;
> + void *dec_handle;
> + int frame_threads;
> + int got_seqhdr;
> + uavs3d_io_frm_t dec_frame;
> +} UAVS3DContext;
> +
> +
> +static int uavs3d_find_next_start_code(const unsigned char *bs_data, int bs_len, int *left)
> +{
> + const unsigned char *data_ptr = bs_data + 4;
> + int count = bs_len - 4;
> +
> + while (count >= 4 &&
> + ((*(unsigned int *)data_ptr) != 0xB6010000) && /* P/B picture */
This pointer cast will be undefined behaviour, because the data need not be aligned. Even if it were valid, it's still going to give the wrong answer on a machine with different endianness to the one you tested on. Use AV_RB32() or AV_RL32().
> + ((*(unsigned int *)data_ptr) != 0xB3010000) && /* I picture */
> + ((*(unsigned int *)data_ptr) != 0xB0010000) && /* sequence header */
> + ((*(unsigned int *)data_ptr) != 0x00010000) && /* first slice */
> + ((*(unsigned int *)data_ptr) != 0xB1010000)) { /* sequence end */
Make symbolic constants for the magic numbers here.
> + data_ptr++;
> + count--;
> + }
> +
> + if (count >= 4) {
> + *left = count;
> + return 1;
> + }
> +
> + return 0;
> +}
> +
> +static void uavs3d_output_callback(uavs3d_io_frm_t *dec_frame) {
> + uavs3d_io_frm_t frm_out;
> + AVFrame *frm = (AVFrame *)dec_frame->priv;
> + int i;
> +
> + if (!frm) {
> + return;
> + }
> +
> + frm->pts = dec_frame->pts;
> + frm->pkt_dts = dec_frame->dts;
> + frm->pict_type = IMGTYPE[dec_frame->type];
Is overflow possible?
> + frm->key_frame = (frm->pict_type == AV_PICTURE_TYPE_I);
> +
> + for (i = 0; i < 3; i++) {
> + frm_out.width [i] = dec_frame->width[i];
> + frm_out.height[i] = dec_frame->height[i];
> + frm_out.stride[i] = frm->linesize[i];
> + frm_out.buffer[i] = frm->data[i];
> + }
> +
> + uavs3d_img_cpy_cvt(&frm_out, dec_frame, dec_frame->bit_depth);
Is this copy really required? Decoders will normally allow you to reference the frame they hold internally.
Can the call ever fail?
> +}
> +
> +static av_cold int libuavs3d_init(AVCodecContext *avctx)
> +{
> + UAVS3DContext *h = avctx->priv_data;
> + uavs3d_cfg_t cdsc;
> +
> + cdsc.frm_threads = FFMIN(h->frame_threads > 0 ? h->frame_threads : av_cpu_count(), UAVS3D_MAX_FRAME_THREADS);
> + cdsc.check_md5 = 0;
> + h->dec_handle = uavs3d_create(&cdsc, uavs3d_output_callback, NULL);
Can this call fail? (For example, if out of memory.)
> + h->got_seqhdr = 0;
> +
> + return 0;
> +}
> +
> +static av_cold int libuavs3d_end(AVCodecContext *avctx)
> +{
> + UAVS3DContext *h = avctx->priv_data;
> +
> + if (h->dec_handle) {
> + uavs3d_flush(h->dec_handle, NULL);
> + uavs3d_delete(h->dec_handle);
> + h->dec_handle = NULL;
> + }
> + h->got_seqhdr = 0;
> +
> + return 0;
> +}
> +
> +static void libuavs3d_flush(AVCodecContext * avctx)
> +{
> + UAVS3DContext *h = avctx->priv_data;
> + uavs3d_cfg_t cdsc;
> + cdsc.frm_threads = FFMIN(h->frame_threads > 0 ? h->frame_threads : av_cpu_count(), UAVS3D_MAX_FRAME_THREADS);
> + cdsc.check_md5 = 0;
> +
> + if (h->dec_handle) {
> + uavs3d_flush(h->dec_handle, NULL);
> + uavs3d_delete(h->dec_handle);
> + }
> +
> + h->dec_handle = uavs3d_create(&cdsc, uavs3d_output_callback, NULL);
> + h->got_seqhdr = 0;
> +}
> +
> +static int libuavs3d_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
> +{
> + UAVS3DContext *h = avctx->priv_data;
> + const uint8_t *buf = avpkt->data;
> + int buf_size = avpkt->size;
> + const uint8_t *buf_end;
> + const uint8_t *buf_ptr;
> + AVFrame *frm = (AVFrame*)data;
No need for explicit casts from void*.
> + int left_bytes;
> + int ret, finish = 0;
> +
> + *got_frame = 0;
> + frm->pts = -1;
> + frm->pict_type = AV_PICTURE_TYPE_NONE;
> +
> + if (h->got_seqhdr) {
> + if (!frm->data[0] && (ret = ff_get_buffer(avctx, frm, 0)) < 0) {
> + return ret;
> + }
> + h->dec_frame.priv = data; // AVFrame
Always allocating here if you have sequence header looks suspicious. What if you don't get any frame output?
> + }
> +
> + if (!buf_size) {
> + do {
> + ret = uavs3d_flush(h->dec_handle, &h->dec_frame);
> + } while (ret > 0 && !h->dec_frame.got_pic);
> + } else {
> + buf_ptr = buf;
> + buf_end = buf + buf_size;
> +
> + while (!finish) {
> + int bs_len;
> + uavs3d_io_frm_t *frm_dec = &h->dec_frame;
> +
> + if (uavs3d_find_next_start_code(buf_ptr, buf_end - buf_ptr, &left_bytes)) {
> + bs_len = buf_end - buf_ptr - left_bytes;
> + } else {
> + bs_len = buf_end - buf_ptr;
> + finish = 1;
> + }
> + frm_dec->bs = (unsigned char *)buf_ptr;
> + frm_dec->bs_len = bs_len;
> + frm_dec->pts = avpkt->pts;
> + frm_dec->dts = avpkt->dts;
> + uavs3d_decode(h->dec_handle, frm_dec);
Does this call return any sort of error?
More generally, what happens if there is an error in decoding? (For example, because the stream is corrupted.)
> + buf_ptr += bs_len;
> +
> + if (frm_dec->nal_type == NAL_SEQ_HEADER) {
> + static const int avs3_fps_num[9] = {0, 240000, 24, 25, 30000, 30, 50, 60000, 60 };
> + static const int avs3_fps_den[9] = {1, 1001, 1, 1, 1001, 1, 1, 1001, 1 };
> + avctx->framerate.num = avs3_fps_num[frm_dec->seqhdr->frame_rate_code];
> + avctx->framerate.den = avs3_fps_den[frm_dec->seqhdr->frame_rate_code];
Same comment as in 2/4 about ff_mpeg12_frame_rate_tab[].
> + avctx->has_b_frames = 1;
Always?
> + avctx->pix_fmt = frm_dec->seqhdr->bit_depth_internal == 8 ? AV_PIX_FMT_YUV420P : AV_PIX_FMT_YUV420P10LE;
> + ff_set_dimensions(avctx, frm_dec->seqhdr->horizontal_size, frm_dec->seqhdr->vertical_size);
> + h->got_seqhdr = 1;
> + }
> + if (frm_dec->got_pic) {
> + break;
> + }
> + }
> + }
> +
> + *got_frame = h->dec_frame.got_pic;
> +
> + return buf_ptr - buf;
> +}
> +
> +#define UAVS3D_OFFSET(x) offsetof(UAVS3DContext, x)
> +#define VE AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_DECODING_PARAM
> +static const AVOption options[] = {
> + { "frame_threads", "number of frame-level threads ", UAVS3D_OFFSET(frame_threads), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, UAVS3D_MAX_FRAME_THREADS, VE },
> + { NULL }
> +};
> +static const AVClass libuavs3d_class = {
> + .class_name = "libuavs3d_class",
> + .item_name = av_default_item_name,
> + .option = options,
> + .version = LIBAVUTIL_VERSION_INT,
> +};
> +
> +AVCodec ff_libuavs3d_decoder = {
> + .name = "libuavs3d",
> + .long_name = NULL_IF_CONFIG_SMALL("uavs3d AVS3-P2/IEEE1857.10 decoder"),
> + .type = AVMEDIA_TYPE_VIDEO,
> + .id = AV_CODEC_ID_AVS3,
> + .priv_data_size = sizeof(UAVS3DContext),
> + .priv_class = &libuavs3d_class,
> + .init = libuavs3d_init,
> + .close = libuavs3d_end,
> + .decode = libuavs3d_decode_frame,
> + .capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY,
> + .flush = libuavs3d_flush,
> + .pix_fmts = (const enum AVPixelFormat[]) { AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV420P10LE, AV_PIX_FMT_NONE },
> +
> + .wrapper_name = "libuavs3d",
> +};
>
- Mark
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