avcodec/videotoolboxenc: ensure bitrate is set in low_delay mode

VideoToolbox doesn't support automatic bitrate in low delay mode.
Check bitrate and show error message so user knows what's going
wrong.

1 files changed, 6 insertions, 0 deletions

diff --git a/libavcodec/videotoolboxenc.c b/libavcodec/videotoolboxenc.c
index f0d3a15897..729072c0b9 100644
--- a/libavcodec/videotoolboxenc.c
+++ b/libavcodec/videotoolboxenc.c
@@ -1711,6 +1711,12 @@ static int vtenc_configure_encoder(AVCodecContext *avctx)
     // low-latency mode: eliminate frame reordering, follow a one-in-one-out encoding mode
     if ((avctx->flags & AV_CODEC_FLAG_LOW_DELAY) &&
         ((avctx->codec_id == AV_CODEC_ID_H264) || (TARGET_CPU_ARM64 && avctx->codec_id == AV_CODEC_ID_HEVC))) {
+        if (!avctx->bit_rate) {
+            av_log(avctx, AV_LOG_ERROR, "Doesn't support automatic bitrate in low_delay mode, "
+                                        "please specify bitrate explicitly\n");
+            status = AVERROR(EINVAL);
+            goto init_cleanup;
+        }
         CFDictionarySetValue(enc_info,
                              compat_keys.kVTVideoEncoderSpecification_EnableLowLatencyRateControl,
                              kCFBooleanTrue);