[FFmpeg-devel] [PATCH] avcodec/libsvtjpegxsenc: set bitrate to a sane default if unset (PR #21193)

[FFmpeg-devel] [PATCH] avcodec/libsvtjpegxsenc: set bitrate to a sane default if unset (PR #21193)

[James Almer via ffmpeg-devel]

PR #21193 opened by James Almer (jamrial)
URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21193
Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21193.patch

Better than failing with an impossibly low bitrate.


>From 5486773347deb61deb12ff62308a083bf716b9b8 Mon Sep 17 00:00:00 2001
From: James Almer <jamrial@gmail.com>
Date: Sun, 14 Dec 2025 12:48:07 -0300
Subject: [PATCH] avcodec/libsvtjpegxsenc: set bitrate to a sane default if
 unset

Better than failing with an impossibly low bitrate.

Signed-off-by: James Almer <jamrial@gmail.com>
---
 libavcodec/libsvtjpegxsenc.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/libavcodec/libsvtjpegxsenc.c b/libavcodec/libsvtjpegxsenc.c
index 2f7ec095df..3afb25c507 100644
--- a/libavcodec/libsvtjpegxsenc.c
+++ b/libavcodec/libsvtjpegxsenc.c
@@ -196,14 +196,17 @@ static av_cold int svt_jpegxs_enc_init(AVCodecContext* avctx) {
     else
         svt_enc->encoder.verbose = VERBOSE_WARNINGS;
 
-    if (avctx->bit_rate <= 0) {
-        av_log(avctx, AV_LOG_ERROR, "bitrate can't be 0\n");
-        return AVERROR(EINVAL);
-    }
     if (avctx->framerate.num <= 0 || avctx->framerate.den <= 0) {
         av_log(avctx, AV_LOG_ERROR, "framerate must be set\n");
         return AVERROR(EINVAL);
     }
+    if (avctx->bit_rate == 0) {
+        const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(avctx->pix_fmt);
+        // default to a 1.5 compression ratio
+        avctx->bit_rate = (int64_t)avctx->width * avctx->height *
+                          (av_get_bits_per_pixel(desc) * 2 / 3) * av_q2d(avctx->framerate);
+        av_log(avctx, AV_LOG_WARNING, "No bitrate set, defaulting to %"PRId64"\n", avctx->bit_rate);
+    }
 
     av_reduce(&bpp.num, &bpp.den, avctx->bit_rate, (int64_t)avctx->width * avctx->height, INT_MAX);
     bpp = av_div_q(bpp, avctx->framerate);
@@ -253,6 +256,11 @@ static const enum AVPixelFormat pix_fmts[] = {
     AV_PIX_FMT_NONE
 };
 
+static const FFCodecDefault svt_jpegxs_defaults[] = {
+    { "b", "0" },
+    { NULL },
+};
+
 #define OFFSET(x) offsetof(SvtJpegXsEncodeContext, x)
 #define VE AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
 static const AVOption svtjpegxs_enc_options[] = {
@@ -288,6 +296,7 @@ const FFCodec ff_libsvtjpegxs_encoder = {
     .priv_data_size = sizeof(SvtJpegXsEncodeContext),
     .init           = svt_jpegxs_enc_init,
     .close          = svt_jpegxs_enc_free,
+    .defaults       = svt_jpegxs_defaults,
     FF_CODEC_ENCODE_CB(svt_jpegxs_enc_encode),
     .p.capabilities = AV_CODEC_CAP_OTHER_THREADS | AV_CODEC_CAP_DR1,
     .caps_internal  = FF_CODEC_CAP_NOT_INIT_THREADSAFE |
-- 
2.49.1

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