[FFmpeg-devel] [PATCH 7/7] avcodec/libx264: add support for param change frame side data

James Almer jamrial at gmail.com
Wed Jan 22 04:54:03 EET 2025


Signed-off-by: James Almer <jamrial at gmail.com>
---
 libavcodec/libx264.c | 98 ++++++++++++++++++++++++++------------------
 1 file changed, 59 insertions(+), 39 deletions(-)

diff --git a/libavcodec/libx264.c b/libavcodec/libx264.c
index 409f45fc7d..c64c2a28b0 100644
--- a/libavcodec/libx264.c
+++ b/libavcodec/libx264.c
@@ -194,54 +194,64 @@ static int encode_nals(AVCodecContext *ctx, AVPacket *pkt,
     return 1;
 }
 
-static void reconfig_encoder(AVCodecContext *ctx, const AVFrame *frame)
+static void reconfig_encoder(AVCodecContext *ctx)
 {
     X264Context *x4 = ctx->priv_data;
-    AVFrameSideData *side_data;
 
+    if (x4->avcintra_class >= 0)
+        return;
 
-    if (x4->avcintra_class < 0) {
-        if (x4->params.b_interlaced && x4->params.b_tff != !!(frame->flags & AV_FRAME_FLAG_TOP_FIELD_FIRST)) {
+    if (x4->params.vui.i_sar_height*ctx->sample_aspect_ratio.num != ctx->sample_aspect_ratio.den * x4->params.vui.i_sar_width) {
+        x4->params.vui.i_sar_height = ctx->sample_aspect_ratio.den;
+        x4->params.vui.i_sar_width  = ctx->sample_aspect_ratio.num;
+        x264_encoder_reconfig(x4->enc, &x4->params);
+    }
 
-            x4->params.b_tff = !!(frame->flags & AV_FRAME_FLAG_TOP_FIELD_FIRST);
-            x264_encoder_reconfig(x4->enc, &x4->params);
-        }
-        if (x4->params.vui.i_sar_height*ctx->sample_aspect_ratio.num != ctx->sample_aspect_ratio.den * x4->params.vui.i_sar_width) {
-            x4->params.vui.i_sar_height = ctx->sample_aspect_ratio.den;
-            x4->params.vui.i_sar_width  = ctx->sample_aspect_ratio.num;
-            x264_encoder_reconfig(x4->enc, &x4->params);
-        }
+    if (x4->params.rc.i_vbv_buffer_size != ctx->rc_buffer_size / 1000 ||
+        x4->params.rc.i_vbv_max_bitrate != ctx->rc_max_rate    / 1000) {
+        x4->params.rc.i_vbv_buffer_size = ctx->rc_buffer_size / 1000;
+        x4->params.rc.i_vbv_max_bitrate = ctx->rc_max_rate    / 1000;
+        x264_encoder_reconfig(x4->enc, &x4->params);
+    }
 
-        if (x4->params.rc.i_vbv_buffer_size != ctx->rc_buffer_size / 1000 ||
-            x4->params.rc.i_vbv_max_bitrate != ctx->rc_max_rate    / 1000) {
-            x4->params.rc.i_vbv_buffer_size = ctx->rc_buffer_size / 1000;
-            x4->params.rc.i_vbv_max_bitrate = ctx->rc_max_rate    / 1000;
-            x264_encoder_reconfig(x4->enc, &x4->params);
-        }
+    if (x4->params.rc.i_rc_method == X264_RC_ABR &&
+        x4->params.rc.i_bitrate != ctx->bit_rate / 1000) {
+        x4->params.rc.i_bitrate = ctx->bit_rate / 1000;
+        x264_encoder_reconfig(x4->enc, &x4->params);
+    }
 
-        if (x4->params.rc.i_rc_method == X264_RC_ABR &&
-            x4->params.rc.i_bitrate != ctx->bit_rate / 1000) {
-            x4->params.rc.i_bitrate = ctx->bit_rate / 1000;
-            x264_encoder_reconfig(x4->enc, &x4->params);
-        }
+    if (x4->crf >= 0 &&
+        x4->params.rc.i_rc_method == X264_RC_CRF &&
+        x4->params.rc.f_rf_constant != x4->crf) {
+        x4->params.rc.f_rf_constant = x4->crf;
+        x264_encoder_reconfig(x4->enc, &x4->params);
+    }
 
-        if (x4->crf >= 0 &&
-            x4->params.rc.i_rc_method == X264_RC_CRF &&
-            x4->params.rc.f_rf_constant != x4->crf) {
-            x4->params.rc.f_rf_constant = x4->crf;
-            x264_encoder_reconfig(x4->enc, &x4->params);
-        }
+    if (x4->params.rc.i_rc_method == X264_RC_CQP &&
+        x4->cqp >= 0 &&
+        x4->params.rc.i_qp_constant != x4->cqp) {
+        x4->params.rc.i_qp_constant = x4->cqp;
+        x264_encoder_reconfig(x4->enc, &x4->params);
+    }
 
-        if (x4->params.rc.i_rc_method == X264_RC_CQP &&
-            x4->cqp >= 0 &&
-            x4->params.rc.i_qp_constant != x4->cqp) {
-            x4->params.rc.i_qp_constant = x4->cqp;
-            x264_encoder_reconfig(x4->enc, &x4->params);
-        }
+    if (x4->crf_max >= 0 &&
+        x4->params.rc.f_rf_constant_max != x4->crf_max) {
+        x4->params.rc.f_rf_constant_max = x4->crf_max;
+        x264_encoder_reconfig(x4->enc, &x4->params);
+    }
+}
 
-        if (x4->crf_max >= 0 &&
-            x4->params.rc.f_rf_constant_max != x4->crf_max) {
-            x4->params.rc.f_rf_constant_max = x4->crf_max;
+static void reconfig_encoder_from_frame(AVCodecContext *ctx, const AVFrame *frame)
+{
+    X264Context *x4 = ctx->priv_data;
+    AVFrameSideData *side_data;
+
+    reconfig_encoder(ctx);
+
+    if (x4->avcintra_class < 0) {
+        if (x4->params.b_interlaced && x4->params.b_tff != !!(frame->flags & AV_FRAME_FLAG_TOP_FIELD_FIRST)) {
+
+            x4->params.b_tff = !!(frame->flags & AV_FRAME_FLAG_TOP_FIELD_FIRST);
             x264_encoder_reconfig(x4->enc, &x4->params);
         }
     }
@@ -528,7 +538,7 @@ static int setup_frame(AVCodecContext *ctx, const AVFrame *frame,
         pic->i_type = X264_TYPE_AUTO;
         break;
     }
-    reconfig_encoder(ctx, frame);
+    reconfig_encoder_from_frame(ctx, frame);
 
     if (x4->a53_cc) {
         void *sei_data;
@@ -759,6 +769,14 @@ static void X264_flush(AVCodecContext *avctx)
         x4->sei_size = -x4->sei_size;
 }
 
+static av_cold int X264_reconf(AVCodecContext *avctx)
+{
+    X264Context *x4 = avctx->priv_data;
+
+    reconfig_encoder(avctx);
+    return 0;
+}
+
 static av_cold int X264_close(AVCodecContext *avctx)
 {
     X264Context *x4 = avctx->priv_data;
@@ -1624,6 +1642,7 @@ const FFCodec ff_libx264_encoder = {
                         AV_CODEC_CAP_OTHER_THREADS |
                         AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE |
                         AV_CODEC_CAP_ENCODER_FLUSH |
+                        AV_CODEC_CAP_PARAM_CHANGE |
                         AV_CODEC_CAP_ENCODER_RECON_FRAME,
     .p.priv_class     = &x264_class,
     .p.wrapper_name   = "libx264",
@@ -1631,6 +1650,7 @@ const FFCodec ff_libx264_encoder = {
     .init             = X264_init,
     FF_CODEC_ENCODE_CB(X264_frame),
     .flush            = X264_flush,
+    .reconf           = X264_reconf,
     .close            = X264_close,
     .defaults         = x264_defaults,
     .p.pix_fmts       = pix_fmts_all,
-- 
2.48.1



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