88 lines
2.2 KiB
C
88 lines
2.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Coda multi-standard codec IP - MPEG-2 helper functions
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*
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* Copyright (C) 2019 Pengutronix, Philipp Zabel
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*/
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#include <linux/kernel.h>
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#include <linux/videodev2.h>
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#include "coda.h"
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int coda_mpeg2_profile(int profile_idc)
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{
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switch (profile_idc) {
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case 5:
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return V4L2_MPEG_VIDEO_MPEG2_PROFILE_SIMPLE;
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case 4:
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return V4L2_MPEG_VIDEO_MPEG2_PROFILE_MAIN;
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case 3:
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return V4L2_MPEG_VIDEO_MPEG2_PROFILE_SNR_SCALABLE;
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case 2:
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return V4L2_MPEG_VIDEO_MPEG2_PROFILE_SPATIALLY_SCALABLE;
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case 1:
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return V4L2_MPEG_VIDEO_MPEG2_PROFILE_HIGH;
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default:
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return -EINVAL;
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}
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}
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int coda_mpeg2_level(int level_idc)
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{
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switch (level_idc) {
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case 10:
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return V4L2_MPEG_VIDEO_MPEG2_LEVEL_LOW;
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case 8:
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return V4L2_MPEG_VIDEO_MPEG2_LEVEL_MAIN;
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case 6:
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return V4L2_MPEG_VIDEO_MPEG2_LEVEL_HIGH_1440;
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case 4:
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return V4L2_MPEG_VIDEO_MPEG2_LEVEL_HIGH;
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default:
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return -EINVAL;
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}
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}
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/*
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* Check if the buffer starts with the MPEG-2 sequence header (with or without
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* quantization matrix) and extension header, for example:
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*
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* 00 00 01 b3 2d 01 e0 34 08 8b a3 81
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* 10 11 11 12 12 12 13 13 13 13 14 14 14 14 14 15
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* 15 15 15 15 15 16 16 16 16 16 16 16 17 17 17 17
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* 17 17 17 17 18 18 18 19 18 18 18 19 1a 1a 1a 1a
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* 19 1b 1b 1b 1b 1b 1c 1c 1c 1c 1e 1e 1e 1f 1f 21
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* 00 00 01 b5 14 8a 00 01 00 00
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*
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* or:
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*
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* 00 00 01 b3 08 00 40 15 ff ff e0 28
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* 00 00 01 b5 14 8a 00 01 00 00
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*
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* Returns the detected header size in bytes or 0.
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*/
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u32 coda_mpeg2_parse_headers(struct coda_ctx *ctx, u8 *buf, u32 size)
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{
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static const u8 sequence_header_start[4] = { 0x00, 0x00, 0x01, 0xb3 };
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static const union {
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u8 extension_start[4];
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u8 start_code_prefix[3];
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} u = { { 0x00, 0x00, 0x01, 0xb5 } };
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if (size < 22 ||
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memcmp(buf, sequence_header_start, 4) != 0)
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return 0;
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if ((size == 22 ||
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(size >= 25 && memcmp(buf + 22, u.start_code_prefix, 3) == 0)) &&
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memcmp(buf + 12, u.extension_start, 4) == 0)
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return 22;
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if ((size == 86 ||
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(size > 89 && memcmp(buf + 86, u.start_code_prefix, 3) == 0)) &&
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memcmp(buf + 76, u.extension_start, 4) == 0)
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return 86;
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return 0;
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}
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