libavcodec/vmixdec.c - third_party/ffmpeg - Git at Google

 /*
  * vMix decoder
  * Copyright (c) 2023 Paul B Mahol
  *
  * 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 <stdio.h>
 #include <stdlib.h>
 #include <string.h>

 #include "libavutil/intreadwrite.h"
 #include "libavutil/mem.h"
 #include "libavutil/mem_internal.h"

 #include "avcodec.h"
 #include "codec_internal.h"
 #define CACHED_BITSTREAM_READER !ARCH_X86_32
 #include "golomb.h"
 #include "get_bits.h"
 #include "idctdsp.h"
 #include "thread.h"

 typedef struct SliceContext {
     const uint8_t *dc_ptr;
     const uint8_t *ac_ptr;
     unsigned dc_size;
     unsigned ac_size;
 } SliceContext;

 typedef struct VMIXContext {
     int nb_slices;
     int lshift;

     int16_t factors[64];
     uint8_t scan[64];

     SliceContext *slices;
     unsigned int slices_size;

     IDCTDSPContext idsp;
 } VMIXContext;

 static const uint8_t quality[] = {
     1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
     1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
     1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
     1, 1, 1, 1, 1, 1,64,63,62,61,
    60,59,58,57,56,55,54,53,52,51,
    50,49,48,47,46,45,44,43,42,41,
    40,39,38,37,36,35,34,33,32,31,
    30,29,28,27,26,25,24,23,22,21,
    20,19,18,17,16,15,14,13,12,11,
    10, 9, 8, 7, 6, 5, 4, 3, 2, 1,
 };

 static const uint8_t quant[64] = {
     16, 16, 19, 22, 22, 26, 26, 27,
     16, 16, 22, 22, 26, 27, 27, 29,
     19, 22, 26, 26, 27, 29, 29, 35,
     22, 24, 27, 27, 29, 32, 34, 38,
     26, 27, 29, 29, 32, 35, 38, 46,
     27, 29, 34, 34, 35, 40, 46, 56,
     29, 34, 34, 37, 40, 48, 56, 69,
     34, 37, 38, 40, 48, 58, 69, 83,
 };

 static av_cold int decode_init(AVCodecContext *avctx)
 {
     VMIXContext *s = avctx->priv_data;

     avctx->bits_per_raw_sample = 8;
     avctx->pix_fmt = AV_PIX_FMT_YUV422P;

     avctx->coded_width = FFALIGN(avctx->width, 16);
     avctx->coded_height = FFALIGN(avctx->height, 16);

     ff_idctdsp_init(&s->idsp, avctx);
     ff_permute_scantable(s->scan, ff_zigzag_direct,
                          s->idsp.idct_permutation);
     return 0;
 }

 static inline int get_se_golomb_vmix(GetBitContext *gb)
 {
     unsigned int buf = get_ue_golomb_long(gb);
     int sign = (buf & 1) - 1;
     return ((buf >> 1) ^ (~sign));
 }

 static int decode_dcac(AVCodecContext *avctx,
                        GetBitContext *dc_gb, GetBitContext *ac_gb,
                        unsigned *dcrun, unsigned *acrun,
                        AVFrame *frame, int width, int by, int plane)
 {
     const ptrdiff_t linesize = frame->linesize[plane];
     uint8_t *dst = frame->data[plane] + by * linesize;
     unsigned dc_run = *dcrun, ac_run = *acrun;
     LOCAL_ALIGNED_32(int16_t, block, [64]);
     VMIXContext *s = avctx->priv_data;
     const int16_t *factors = s->factors;
     const uint8_t *scan = s->scan;
     const int add = plane ? 0 : 1024;
     int i, dc_v = 0, ac_v = 0, dc = 0;
     const int lshift = s->lshift;

     for (int y = 0; y < 2; y++) {
         for (int x = 0; x < width; x += 8) {
             memset(block, 0, sizeof(*block)*64);

             if (dc_run > 0) {
                 dc_run--;
             } else {
                 if (get_bits_left(dc_gb) < 1)
                     return AVERROR_INVALIDDATA;
                 dc_v = get_se_golomb_vmix(dc_gb);
                 dc += (unsigned)dc_v;
                 if (!dc_v)
                     dc_run = get_ue_golomb_long(dc_gb);
             }

             for (int n = 0; n < 64; n++) {
                 if (ac_run > 0) {
                     ac_run--;
                     continue;
                 }

                 if (get_bits_left(ac_gb) < 1)
                     return AVERROR_INVALIDDATA;
                 ac_v = get_se_golomb_vmix(ac_gb);
                 i = scan[n];
                 block[i] = ((unsigned)ac_v * factors[i]) >> 4;
                 if (!ac_v)
                     ac_run = get_ue_golomb_long(ac_gb);
             }

             block[0] = ((unsigned)dc << lshift) + (unsigned)add;
             s->idsp.idct_put(dst + x, linesize, block);
         }

         dst += 8 * linesize;
     }

     *dcrun = dc_run;
     *acrun = ac_run;

     return 0;
 }

 static int decode_slice(AVCodecContext *avctx, AVFrame *frame,
                         const uint8_t *dc_src, unsigned dc_slice_size,
                         const uint8_t *ac_src, unsigned ac_slice_size,
                         int by)
 {
     unsigned dc_run = 0, ac_run = 0;
     GetBitContext dc_gb, ac_gb;
     int ret;

     ret = init_get_bits8(&dc_gb, dc_src, dc_slice_size);
     if (ret < 0)
         return ret;

     ret = init_get_bits8(&ac_gb, ac_src, ac_slice_size);
     if (ret < 0)
         return ret;

     for (int p = 0; p < 3; p++) {
         const int rshift = !!p;
         ret = decode_dcac(avctx, &dc_gb, &ac_gb,
                           &dc_run, &ac_run, frame,
                           frame->width >> rshift, by, p);
         if (ret < 0)
             return ret;

         if (get_bits_left(&dc_gb) < 0)
             return AVERROR_INVALIDDATA;
         if (get_bits_left(&ac_gb) < 0)
             return AVERROR_INVALIDDATA;

         align_get_bits(&dc_gb);
         align_get_bits(&ac_gb);
     }

     if (get_bits_left(&dc_gb) > 0)
         return AVERROR_INVALIDDATA;
     if (get_bits_left(&ac_gb) > 0)
         return AVERROR_INVALIDDATA;

     return 0;
 }

 static int decode_slices(AVCodecContext *avctx, void *arg,
                          int n, int thread_nb)
 {
     VMIXContext *s = avctx->priv_data;
     const uint8_t *dc_slice_ptr = s->slices[n].dc_ptr;
     const uint8_t *ac_slice_ptr = s->slices[n].ac_ptr;
     unsigned dc_slice_size = s->slices[n].dc_size;
     unsigned ac_slice_size = s->slices[n].ac_size;
     AVFrame *frame = arg;

     return decode_slice(avctx, frame, dc_slice_ptr, dc_slice_size,
                         ac_slice_ptr, ac_slice_size, n * 16);
 }

 static int decode_frame(AVCodecContext *avctx,
                         AVFrame *frame, int *got_frame,
                         AVPacket *avpkt)
 {
     VMIXContext *s = avctx->priv_data;
     unsigned offset, q;
     int ret;

     if (avpkt->size <= 7)
         return AVERROR_INVALIDDATA;

     s->lshift = 0;
     offset = 2 + avpkt->data[0];
     if (offset == 5)
         s->lshift = avpkt->data[1];
     else if (offset != 3)
         return AVERROR_INVALIDDATA;

     if (s->lshift > 31)
         return AVERROR_INVALIDDATA;

     q = quality[FFMIN(avpkt->data[offset - 2], FF_ARRAY_ELEMS(quality)-1)];
     for (int n = 0; n < 64; n++)
         s->factors[n] = quant[n] * q;

     s->nb_slices = (avctx->height + 15) / 16;
     av_fast_mallocz(&s->slices, &s->slices_size, s->nb_slices * sizeof(*s->slices));
     if (!s->slices)
         return AVERROR(ENOMEM);

     for (int n = 0; n < s->nb_slices; n++) {
         unsigned slice_size;

         if (offset + 4 > avpkt->size)
             return AVERROR_INVALIDDATA;

         slice_size = AV_RL32(avpkt->data + offset);
         if (slice_size > avpkt->size)
             return AVERROR_INVALIDDATA;

         if (avpkt->size - slice_size - 4LL < offset)
             return AVERROR_INVALIDDATA;

         s->slices[n].dc_size = slice_size;
         s->slices[n].dc_ptr = avpkt->data + offset + 4;
         offset += slice_size + 4;
     }

     for (int n = 0; n < s->nb_slices; n++) {
         unsigned slice_size;

         if (offset + 4 > avpkt->size)
             return AVERROR_INVALIDDATA;

         slice_size = AV_RL32(avpkt->data + offset);
         if (slice_size > avpkt->size)
             return AVERROR_INVALIDDATA;

         if (avpkt->size - slice_size - 4LL < offset)
             return AVERROR_INVALIDDATA;

         s->slices[n].ac_size = slice_size;
         s->slices[n].ac_ptr = avpkt->data + offset + 4;
         offset += slice_size + 4;
     }

     ret = ff_thread_get_buffer(avctx, frame, 0);
     if (ret < 0)
         return ret;

     avctx->execute2(avctx, decode_slices, frame, NULL, s->nb_slices);

     frame->pict_type = AV_PICTURE_TYPE_I;
     frame->flags |= AV_FRAME_FLAG_KEY;

     *got_frame = 1;

     return avpkt->size;
 }

 static av_cold int decode_end(AVCodecContext *avctx)
 {
     VMIXContext *s = avctx->priv_data;
     av_freep(&s->slices);
     return 0;
 }

 const FFCodec ff_vmix_decoder = {
     .p.name           = "vmix",
     CODEC_LONG_NAME("vMix Video"),
     .p.type           = AVMEDIA_TYPE_VIDEO,
     .p.id             = AV_CODEC_ID_VMIX,
     .priv_data_size   = sizeof(VMIXContext),
     .init             = decode_init,
     .close            = decode_end,
     FF_CODEC_DECODE_CB(decode_frame),
     .p.capabilities   = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS |
                         AV_CODEC_CAP_SLICE_THREADS,
 };
	/*
	* vMix decoder
	* Copyright (c) 2023 Paul B Mahol
	*
	* 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 <stdio.h>
	#include <stdlib.h>
	#include <string.h>

	#include "libavutil/intreadwrite.h"
	#include "libavutil/mem.h"
	#include "libavutil/mem_internal.h"

	#include "avcodec.h"
	#include "codec_internal.h"
	#define CACHED_BITSTREAM_READER !ARCH_X86_32
	#include "golomb.h"
	#include "get_bits.h"
	#include "idctdsp.h"
	#include "thread.h"

	typedef struct SliceContext {
	const uint8_t *dc_ptr;
	const uint8_t *ac_ptr;
	unsigned dc_size;
	unsigned ac_size;
	} SliceContext;

	typedef struct VMIXContext {
	int nb_slices;
	int lshift;

	int16_t factors[64];
	uint8_t scan[64];

	SliceContext *slices;
	unsigned int slices_size;

	IDCTDSPContext idsp;
	} VMIXContext;

	static const uint8_t quality[] = {
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
	1, 1, 1, 1, 1, 1,64,63,62,61,
	60,59,58,57,56,55,54,53,52,51,
	50,49,48,47,46,45,44,43,42,41,
	40,39,38,37,36,35,34,33,32,31,
	30,29,28,27,26,25,24,23,22,21,
	20,19,18,17,16,15,14,13,12,11,
	10, 9, 8, 7, 6, 5, 4, 3, 2, 1,
	};

	static const uint8_t quant[64] = {
	16, 16, 19, 22, 22, 26, 26, 27,
	16, 16, 22, 22, 26, 27, 27, 29,
	19, 22, 26, 26, 27, 29, 29, 35,
	22, 24, 27, 27, 29, 32, 34, 38,
	26, 27, 29, 29, 32, 35, 38, 46,
	27, 29, 34, 34, 35, 40, 46, 56,
	29, 34, 34, 37, 40, 48, 56, 69,
	34, 37, 38, 40, 48, 58, 69, 83,
	};

	static av_cold int decode_init(AVCodecContext *avctx)
	{
	VMIXContext *s = avctx->priv_data;

	avctx->bits_per_raw_sample = 8;
	avctx->pix_fmt = AV_PIX_FMT_YUV422P;

	avctx->coded_width = FFALIGN(avctx->width, 16);
	avctx->coded_height = FFALIGN(avctx->height, 16);

	ff_idctdsp_init(&s->idsp, avctx);
	ff_permute_scantable(s->scan, ff_zigzag_direct,
	s->idsp.idct_permutation);
	return 0;
	}

	static inline int get_se_golomb_vmix(GetBitContext *gb)
	{
	unsigned int buf = get_ue_golomb_long(gb);
	int sign = (buf & 1) - 1;
	return ((buf >> 1) ^ (~sign));
	}

	static int decode_dcac(AVCodecContext *avctx,
	GetBitContext dc_gb, GetBitContext ac_gb,
	unsigned dcrun, unsigned acrun,
	AVFrame *frame, int width, int by, int plane)
	{
	const ptrdiff_t linesize = frame->linesize[plane];
	uint8_t dst = frame->data[plane] + by linesize;
	unsigned dc_run = dcrun, ac_run = acrun;
	LOCAL_ALIGNED_32(int16_t, block, [64]);
	VMIXContext *s = avctx->priv_data;
	const int16_t *factors = s->factors;
	const uint8_t *scan = s->scan;
	const int add = plane ? 0 : 1024;
	int i, dc_v = 0, ac_v = 0, dc = 0;
	const int lshift = s->lshift;

	for (int y = 0; y < 2; y++) {
	for (int x = 0; x < width; x += 8) {
	memset(block, 0, sizeof(block)64);

	if (dc_run > 0) {
	dc_run--;
	} else {
	if (get_bits_left(dc_gb) < 1)
	return AVERROR_INVALIDDATA;
	dc_v = get_se_golomb_vmix(dc_gb);
	dc += (unsigned)dc_v;
	if (!dc_v)
	dc_run = get_ue_golomb_long(dc_gb);
	}

	for (int n = 0; n < 64; n++) {
	if (ac_run > 0) {
	ac_run--;
	continue;
	}

	if (get_bits_left(ac_gb) < 1)
	return AVERROR_INVALIDDATA;
	ac_v = get_se_golomb_vmix(ac_gb);
	i = scan[n];
	block[i] = ((unsigned)ac_v * factors[i]) >> 4;
	if (!ac_v)
	ac_run = get_ue_golomb_long(ac_gb);
	}

	block[0] = ((unsigned)dc << lshift) + (unsigned)add;
	s->idsp.idct_put(dst + x, linesize, block);
	}

	dst += 8 * linesize;
	}

	*dcrun = dc_run;
	*acrun = ac_run;

	return 0;
	}

	static int decode_slice(AVCodecContext avctx, AVFrame frame,
	const uint8_t *dc_src, unsigned dc_slice_size,
	const uint8_t *ac_src, unsigned ac_slice_size,
	int by)
	{
	unsigned dc_run = 0, ac_run = 0;
	GetBitContext dc_gb, ac_gb;
	int ret;

	ret = init_get_bits8(&dc_gb, dc_src, dc_slice_size);
	if (ret < 0)
	return ret;

	ret = init_get_bits8(&ac_gb, ac_src, ac_slice_size);
	if (ret < 0)
	return ret;

	for (int p = 0; p < 3; p++) {
	const int rshift = !!p;
	ret = decode_dcac(avctx, &dc_gb, &ac_gb,
	&dc_run, &ac_run, frame,
	frame->width >> rshift, by, p);
	if (ret < 0)
	return ret;

	if (get_bits_left(&dc_gb) < 0)
	return AVERROR_INVALIDDATA;
	if (get_bits_left(&ac_gb) < 0)
	return AVERROR_INVALIDDATA;

	align_get_bits(&dc_gb);
	align_get_bits(&ac_gb);
	}

	if (get_bits_left(&dc_gb) > 0)
	return AVERROR_INVALIDDATA;
	if (get_bits_left(&ac_gb) > 0)
	return AVERROR_INVALIDDATA;

	return 0;
	}

	static int decode_slices(AVCodecContext avctx, void arg,
	int n, int thread_nb)
	{
	VMIXContext *s = avctx->priv_data;
	const uint8_t *dc_slice_ptr = s->slices[n].dc_ptr;
	const uint8_t *ac_slice_ptr = s->slices[n].ac_ptr;
	unsigned dc_slice_size = s->slices[n].dc_size;
	unsigned ac_slice_size = s->slices[n].ac_size;
	AVFrame *frame = arg;

	return decode_slice(avctx, frame, dc_slice_ptr, dc_slice_size,
	ac_slice_ptr, ac_slice_size, n * 16);
	}

	static int decode_frame(AVCodecContext *avctx,
	AVFrame frame, int got_frame,
	AVPacket *avpkt)
	{
	VMIXContext *s = avctx->priv_data;
	unsigned offset, q;
	int ret;

	if (avpkt->size <= 7)
	return AVERROR_INVALIDDATA;

	s->lshift = 0;
	offset = 2 + avpkt->data[0];
	if (offset == 5)
	s->lshift = avpkt->data[1];
	else if (offset != 3)
	return AVERROR_INVALIDDATA;

	if (s->lshift > 31)
	return AVERROR_INVALIDDATA;

	q = quality[FFMIN(avpkt->data[offset - 2], FF_ARRAY_ELEMS(quality)-1)];
	for (int n = 0; n < 64; n++)
	s->factors[n] = quant[n] * q;

	s->nb_slices = (avctx->height + 15) / 16;
	av_fast_mallocz(&s->slices, &s->slices_size, s->nb_slices * sizeof(*s->slices));
	if (!s->slices)
	return AVERROR(ENOMEM);

	for (int n = 0; n < s->nb_slices; n++) {
	unsigned slice_size;

	if (offset + 4 > avpkt->size)
	return AVERROR_INVALIDDATA;

	slice_size = AV_RL32(avpkt->data + offset);
	if (slice_size > avpkt->size)
	return AVERROR_INVALIDDATA;

	if (avpkt->size - slice_size - 4LL < offset)
	return AVERROR_INVALIDDATA;

	s->slices[n].dc_size = slice_size;
	s->slices[n].dc_ptr = avpkt->data + offset + 4;
	offset += slice_size + 4;
	}

	for (int n = 0; n < s->nb_slices; n++) {
	unsigned slice_size;

	if (offset + 4 > avpkt->size)
	return AVERROR_INVALIDDATA;

	slice_size = AV_RL32(avpkt->data + offset);
	if (slice_size > avpkt->size)
	return AVERROR_INVALIDDATA;

	if (avpkt->size - slice_size - 4LL < offset)
	return AVERROR_INVALIDDATA;

	s->slices[n].ac_size = slice_size;
	s->slices[n].ac_ptr = avpkt->data + offset + 4;
	offset += slice_size + 4;
	}

	ret = ff_thread_get_buffer(avctx, frame, 0);
	if (ret < 0)
	return ret;

	avctx->execute2(avctx, decode_slices, frame, NULL, s->nb_slices);

	frame->pict_type = AV_PICTURE_TYPE_I;
	frame->flags \|= AV_FRAME_FLAG_KEY;

	*got_frame = 1;

	return avpkt->size;
	}

	static av_cold int decode_end(AVCodecContext *avctx)
	{
	VMIXContext *s = avctx->priv_data;
	av_freep(&s->slices);
	return 0;
	}

	const FFCodec ff_vmix_decoder = {
	.p.name = "vmix",
	CODEC_LONG_NAME("vMix Video"),
	.p.type = AVMEDIA_TYPE_VIDEO,
	.p.id = AV_CODEC_ID_VMIX,
	.priv_data_size = sizeof(VMIXContext),
	.init = decode_init,
	.close = decode_end,
	FF_CODEC_DECODE_CB(decode_frame),
	.p.capabilities = AV_CODEC_CAP_DR1 \| AV_CODEC_CAP_FRAME_THREADS \|
	AV_CODEC_CAP_SLICE_THREADS,
	};