On 31/10/17 15:11, Jun Zhao wrote:> On 2017/10/31 18:19, Mark Thompson wrote:
>> On 31/10/17 02:37, Jun Zhao wrote:
>>> From 7eef9be1c8a92bf625d62a0f97f762f1342c6d78 Mon Sep 17 00:00:00 2001
>>> From: Jun Zhao <jun.z...@intel.com>
>>> Date: Tue, 31 Oct 2017 10:13:42 +0800
>>> Subject: [PATCH 1/2] lavc/vaapi_encode: correct the HRD buffer size
>>> calculate.
>>>
>>> when rc_buffer_size didn't setting, always use the max bit rate
>>> per second as HRD buffer size.
>>>
>>> Signed-off-by: Jun Zhao <jun.z...@intel.com>
>>> Signed-off-by: Wang, Yi A <yi.a.w...@intel.com>
>>> ---
>>> libavcodec/vaapi_encode.c | 21 ++++++++++-----------
>>> 1 file changed, 10 insertions(+), 11 deletions(-)
>>>
>>> diff --git a/libavcodec/vaapi_encode.c b/libavcodec/vaapi_encode.c
>>> index 590f4be4ed..d5f89ef346 100644
>>> --- a/libavcodec/vaapi_encode.c
>>> +++ b/libavcodec/vaapi_encode.c
>>> @@ -1144,19 +1144,9 @@ static av_cold int
>>> vaapi_encode_init_rate_control(AVCodecContext *avctx)
>>> return AVERROR(EINVAL);
>>> }
>>>
>>> - if (avctx->rc_buffer_size)
>>> - hrd_buffer_size = avctx->rc_buffer_size;
>>> - else
>>> - hrd_buffer_size = avctx->bit_rate;
>>> - if (avctx->rc_initial_buffer_occupancy)
>>> - hrd_initial_buffer_fullness = avctx->rc_initial_buffer_occupancy;
>>> - else
>>> - hrd_initial_buffer_fullness = hrd_buffer_size * 3 / 4;
>>> -
>>> if (ctx->va_rc_mode == VA_RC_CBR) {
>>> rc_bits_per_second = avctx->bit_rate;
>>> rc_target_percentage = 100;
>>> - rc_window_size = 1000;
>>> } else {
>>> if (avctx->rc_max_rate < avctx->bit_rate) {
>>> // Max rate is unset or invalid, just use the normal bitrate.
>>> @@ -1166,8 +1156,17 @@ static av_cold int
>>> vaapi_encode_init_rate_control(AVCodecContext *avctx)
>>> rc_bits_per_second = avctx->rc_max_rate;
>>> rc_target_percentage = (avctx->bit_rate * 100) /
>>> rc_bits_per_second;
>>> }
>>> - rc_window_size = (hrd_buffer_size * 1000) / avctx->bit_rate;
>>> }
>>> + rc_window_size = (rc_bits_per_second * 1000) / avctx->bit_rate;
>>> +
>>> + if (avctx->rc_buffer_size)
>>> + hrd_buffer_size = avctx->rc_buffer_size;
>>> + else
>>> + hrd_buffer_size = rc_bits_per_second;
>>> + if (avctx->rc_initial_buffer_occupancy)
>>> + hrd_initial_buffer_fullness = avctx->rc_initial_buffer_occupancy;
>>> + else
>>> + hrd_initial_buffer_fullness = hrd_buffer_size * 3 / 4;
>>>
>>> ctx->rc_params.misc.type = VAEncMiscParameterTypeRateControl;
>>> ctx->rc_params.rc = (VAEncMiscParameterRateControl) {
>>> --
>>> 2.14.1
>>>
>> Why? If the RC buffer size is unset it currently guesses one second of the
>> target bitrate - in what way is the peak bitrate any more appropriate as a
>> guess?
> In VBR mode, when rc_max_rate more than bit_rate, I think HDR size need
> to use rc_max_rate, not the bit_rate.
Ok, why do you think that? I'm not necessarily against this change (in cases
where it matters the user will provide rc_buffer_size explicitly), but please
provide some reasoning for it.
- Mark
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