From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org [79.124.17.100]) by master.gitmailbox.com (Postfix) with ESMTPS id 64FB54BA8F for ; Sun, 2 Mar 2025 17:24:02 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 4453368E35D; Sun, 2 Mar 2025 19:23:58 +0200 (EET) Received: from smtp.waider.ie (smtp.waider.ie [52.31.250.228]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id D6FF568E0BA for ; Sun, 2 Mar 2025 19:23:48 +0200 (EET) Received: from localhost.localdomain (unknown [109.255.224.49]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.waider.ie (Postfix) with ESMTPSA id 2234149D45; Sun, 2 Mar 2025 17:23:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=waider.ie; s=waider_ie; t=1740936228; bh=RtzuwBmxKKNLJHMwdrWi4RK3B2U/GRhdU9r/JKSPYpk=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Transfer-Encoding; b=LwLO24NPodwzAUVOOD+R2KR1c8JN5QC/QCp9khLGSFfySf/vu5kuVxKCIbjYI2jzY b/ruKciud7KMdbBk2fb6mHdo2VxBgXMB/zUJwO5JIKOczD4cXGlsp/rKb6+2dV76Hm CmrlRWYaWh1PD8AiIC9l3sGojmSIdHjfseAR8CW8= From: Ronan Waide To: ffmpeg-devel@ffmpeg.org Date: Sun, 2 Mar 2025 17:23:31 +0000 Message-Id: <20250302172331.57779-1-waider@waider.ie> X-Mailer: git-send-email 2.39.5 (Apple Git-154) In-Reply-To: References: MIME-Version: 1.0 X-Spam-Status: No, score=-102.9 required=5.0 tests=ALL_TRUSTED,BAYES_00, USER_IN_WELCOMELIST,USER_IN_WHITELIST autolearn=ham autolearn_force=no version=3.4.3 X-Spam-Checker-Version: SpamAssassin 3.4.3 (2019-12-06) on ec2.waider.ie Subject: [FFmpeg-devel] [PATCH v5] libavcodec/dvbsubenc.c: add a disable_2bpp option to work around some decoders. X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: FFmpeg development discussions and patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: FFmpeg development discussions and patches Cc: Ronan Waide Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: As noted in the code in several places, some DVB subtitle decoders don't handle 2bpp color. This patch adds a disable_2bpp option which disables the 2bpp format; subtitles which would use 2bpp will be bumped up to 4bpp. Per suggestion from sw, disable_2pp defaults to true. Signed-off-by: Ronan Waide --- doc/encoders.texi | 27 +++++++++++++++++ libavcodec/dvbsubenc.c | 69 +++++++++++++++++++++++++++++++----------- 2 files changed, 78 insertions(+), 18 deletions(-) diff --git a/doc/encoders.texi b/doc/encoders.texi index f3fcc1aa60..6ee0065c7d 100644 --- a/doc/encoders.texi +++ b/doc/encoders.texi @@ -4484,6 +4484,33 @@ Reduces detail but attempts to preserve color at extremely low bitrates. @chapter Subtitles Encoders @c man begin SUBTITLES ENCODERS +@section dvbsub + +This codec encodes the bitmap subtitle format that is used in DVB +broadcasts and recordings. The bitmaps are typically embedded in a +container such as MPEG-TS as a separate stream. + +@subsection Options + +@table @option +@item disable_2bpp @var{boolean} +Disable the 2 bits-per-pixel encoding format. + +DVB supports 2, 4, and 8 bits-per-pixel color lookup tables. However, +not all players support or properly support 2 bits-per-pixel, +resulting in unusable subtitles. +@table @option +@item 0 +The 2 bits-per-pixel encoding format will be used for subtitles with 4 +colors or less. + +@item 1 +The 2 bits-per-pixel encoding format will be disabled, and subtitles +with 4 colors or less will use a 4 bits-per-pixel format. (default) +@end table + +@end table + @section dvdsub This codec encodes the bitmap subtitle format that is used in DVDs. diff --git a/libavcodec/dvbsubenc.c b/libavcodec/dvbsubenc.c index 822e3a5309..4db2e1ddda 100644 --- a/libavcodec/dvbsubenc.c +++ b/libavcodec/dvbsubenc.c @@ -22,9 +22,12 @@ #include "bytestream.h" #include "codec_internal.h" #include "libavutil/colorspace.h" +#include "libavutil/opt.h" typedef struct DVBSubtitleContext { + AVClass * class; int object_version; + int disable_2bpp; } DVBSubtitleContext; #define PUTBITS2(val)\ @@ -274,13 +277,15 @@ static int dvbsub_encode(AVCodecContext *avctx, uint8_t *outbuf, int buf_size, { DVBSubtitleContext *s = avctx->priv_data; uint8_t *q, *pseg_len; - int page_id, region_id, clut_id, object_id, i, bpp_index, page_state; + int page_id, region_id, clut_id, object_id, i, bpp_index, page_state, min_colors; q = outbuf; page_id = 1; + min_colors = s->disable_2bpp ? 16 : 0; + if (h->num_rects && !h->rects) return AVERROR(EINVAL); @@ -326,18 +331,20 @@ static int dvbsub_encode(AVCodecContext *avctx, uint8_t *outbuf, int buf_size, if (h->num_rects) { for (clut_id = 0; clut_id < h->num_rects; clut_id++) { - if (buf_size < 6 + h->rects[clut_id]->nb_colors * 6) + int nb_colors = FFMAX(min_colors, h->rects[clut_id]->nb_colors); + + if (buf_size < 6 + nb_colors * 6) return AVERROR_BUFFER_TOO_SMALL; /* CLUT segment */ - if (h->rects[clut_id]->nb_colors <= 4) { + if (nb_colors <= 4) { /* 2 bpp, some decoders do not support it correctly */ bpp_index = 0; - } else if (h->rects[clut_id]->nb_colors <= 16) { + } else if (nb_colors <= 16) { /* 4 bpp, standard encoding */ bpp_index = 1; - } else if (h->rects[clut_id]->nb_colors <= 256) { + } else if (nb_colors <= 256) { /* 8 bpp, standard encoding */ bpp_index = 2; } else { @@ -354,16 +361,24 @@ static int dvbsub_encode(AVCodecContext *avctx, uint8_t *outbuf, int buf_size, *q++ = clut_id; *q++ = (0 << 4) | 0xf; /* version = 0 */ - for(i = 0; i < h->rects[clut_id]->nb_colors; i++) { + for(i = 0; i < nb_colors; i++) { *q++ = i; /* clut_entry_id */ *q++ = (1 << (7 - bpp_index)) | (0xf << 1) | 1; /* 2 bits/pixel full range */ { int a, r, g, b; - uint32_t x= ((uint32_t*)h->rects[clut_id]->data[1])[i]; - a = (x >> 24) & 0xff; - r = (x >> 16) & 0xff; - g = (x >> 8) & 0xff; - b = (x >> 0) & 0xff; + if (i < h->rects[clut_id]->nb_colors) { + uint32_t x= ((uint32_t*)h->rects[clut_id]->data[1])[i]; + a = (x >> 24) & 0xff; + r = (x >> 16) & 0xff; + g = (x >> 8) & 0xff; + b = (x >> 0) & 0xff; + } else { + /* pad out the CLUT */ + a = 0; + r = 0; + g = 0; + b = 0; + } *q++ = RGB_TO_Y_CCIR(r, g, b); *q++ = RGB_TO_V_CCIR(r, g, b, 0); @@ -373,7 +388,7 @@ static int dvbsub_encode(AVCodecContext *avctx, uint8_t *outbuf, int buf_size, } bytestream_put_be16(&pseg_len, q - pseg_len - 2); - buf_size -= 6 + h->rects[clut_id]->nb_colors * 6; + buf_size -= 6 + nb_colors * 6; } if (buf_size < h->num_rects * 22) @@ -381,14 +396,15 @@ static int dvbsub_encode(AVCodecContext *avctx, uint8_t *outbuf, int buf_size, for (region_id = 0; region_id < h->num_rects; region_id++) { /* region composition segment */ + int nb_colors = FFMAX(min_colors, h->rects[region_id]->nb_colors); - if (h->rects[region_id]->nb_colors <= 4) { + if (nb_colors <= 4) { /* 2 bpp, some decoders do not support it correctly */ bpp_index = 0; - } else if (h->rects[region_id]->nb_colors <= 16) { + } else if (nb_colors <= 16) { /* 4 bpp, standard encoding */ bpp_index = 1; - } else if (h->rects[region_id]->nb_colors <= 256) { + } else if (nb_colors <= 256) { /* 8 bpp, standard encoding */ bpp_index = 2; } else { @@ -424,17 +440,19 @@ static int dvbsub_encode(AVCodecContext *avctx, uint8_t *outbuf, int buf_size, const uint8_t *bitmap, int linesize, int w, int h); + int nb_colors = FFMAX(min_colors, h->rects[object_id]->nb_colors); + if (buf_size < 13) return AVERROR_BUFFER_TOO_SMALL; /* bpp_index maths */ - if (h->rects[object_id]->nb_colors <= 4) { + if (nb_colors <= 4) { /* 2 bpp, some decoders do not support it correctly */ dvb_encode_rle = dvb_encode_rle2; - } else if (h->rects[object_id]->nb_colors <= 16) { + } else if (nb_colors <= 16) { /* 4 bpp, standard encoding */ dvb_encode_rle = dvb_encode_rle4; - } else if (h->rects[object_id]->nb_colors <= 256) { + } else if (nb_colors <= 256) { /* 8 bpp, standard encoding */ dvb_encode_rle = dvb_encode_rle8; } else { @@ -506,6 +524,20 @@ static int dvbsub_encode(AVCodecContext *avctx, uint8_t *outbuf, int buf_size, return q - outbuf; } +#define OFFSET(x) offsetof(DVBSubtitleContext, x) +#define SE AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_ENCODING_PARAM +static const AVOption options[] = { + {"disable_2bpp", "disable the 2bpp subtitle encoder", OFFSET(disable_2bpp), AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, SE}, + { NULL }, +}; + +static const AVClass dvbsubenc_class = { + .class_name = "DVBSUB subtitle encoder", + .item_name = av_default_item_name, + .option = options, + .version = LIBAVUTIL_VERSION_INT, +}; + const FFCodec ff_dvbsub_encoder = { .p.name = "dvbsub", CODEC_LONG_NAME("DVB subtitles"), @@ -513,4 +545,5 @@ const FFCodec ff_dvbsub_encoder = { .p.id = AV_CODEC_ID_DVB_SUBTITLE, .priv_data_size = sizeof(DVBSubtitleContext), FF_CODEC_ENCODE_SUB_CB(dvbsub_encode), + .p.priv_class = &dvbsubenc_class, }; 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