On 27/04/18 05:10, Xiang, Haihao wrote:
> On Sun, 2018-04-22 at 16:29 +0100, Mark Thompson wrote:
>> Query which modes are supported and select between VBR and CBR based
>> on that. Removes all of the codec-specific rate control mode selection
>> code. Also ensures that target percentage and window size match the
>> target bitrate and RC buffer size in all cases where they are not
>> explicitly specified.
>> ---
>> doc/encoders.texi | 2 -
>> libavcodec/vaapi_encode.c | 166
>> ++++++++++++++++++++++++++++-----------
>> -
>> libavcodec/vaapi_encode.h | 4 +-
>> libavcodec/vaapi_encode_h264.c | 12 ---
>> libavcodec/vaapi_encode_h265.c | 12 ---
>> libavcodec/vaapi_encode_mjpeg.c | 3 +-
>> libavcodec/vaapi_encode_mpeg2.c | 3 +-
>> libavcodec/vaapi_encode_vp8.c | 11 ---
>> libavcodec/vaapi_encode_vp9.c | 11 ---
>> 9 files changed, 119 insertions(+), 105 deletions(-)
>>
>> ...
>> diff --git a/libavcodec/vaapi_encode.c b/libavcodec/vaapi_encode.c
>> index fc83d3db11..6188423935 100644
>> --- a/libavcodec/vaapi_encode.c
>> +++ b/libavcodec/vaapi_encode.c
>> ...
>> vaapi_encode_config_attributes(AVCodecContext *avctx)
>> static av_cold int vaapi_encode_init_rate_control(AVCodecContext *avctx)
>> {
>> VAAPIEncodeContext *ctx = avctx->priv_data;
>> - int rc_bits_per_second;
>> - int rc_target_percentage;
>> - int rc_window_size;
>> - int hrd_buffer_size;
>> - int hrd_initial_buffer_fullness;
>> + int64_t rc_bits_per_second;
>> + int rc_target_percentage;
>> + int rc_window_size;
>> + int64_t hrd_buffer_size;
>> + int64_t hrd_initial_buffer_fullness;
>> int fr_num, fr_den;
>> + VAConfigAttrib rc_attr = { VAConfigAttribRateControl };
>> + VAStatus vas;
>> +
>> + vas = vaGetConfigAttributes(ctx->hwctx->display,
>> + ctx->va_profile, ctx->va_entrypoint,
>> + &rc_attr, 1);
>> + if (vas != VA_STATUS_SUCCESS) {
>> + av_log(avctx, AV_LOG_ERROR, "Failed to query rate control "
>> + "config attribute: %d (%s).\n", vas, vaErrorStr(vas));
>> + return AVERROR_EXTERNAL;
>> + }
>>
>> - if (avctx->bit_rate > INT32_MAX) {
>> - av_log(avctx, AV_LOG_ERROR, "Target bitrate of 2^31 bps or "
>> - "higher is not supported.\n");
>> + if (rc_attr.value == VA_ATTRIB_NOT_SUPPORTED) {
>> + av_log(avctx, AV_LOG_VERBOSE, "Driver does not report any "
>> + "supported rate control modes: assuming
>> constant-quality.\n");
>> + ctx->va_rc_mode = VA_RC_CQP;
>> + return 0;
>> + }
>> + if (avctx->flags & AV_CODEC_FLAG_QSCALE ||
>> + avctx->bit_rate <= 0) {
>> + if (rc_attr.value & VA_RC_CQP) {
>> + av_log(avctx, AV_LOG_VERBOSE, "Using constant-quality mode.\n");
>> + ctx->va_rc_mode = VA_RC_CQP;
>> + return 0;
>> + } else {
>> + av_log(avctx, AV_LOG_ERROR, "Driver does not support "
>> + "constant-quality mode (%#x).\n", rc_attr.value);
>> + return AVERROR(EINVAL);
>> + }
>> + }
>> +
>> + if (!(rc_attr.value & (VA_RC_CBR | VA_RC_VBR))) {
>> + av_log(avctx, AV_LOG_ERROR, "Driver does not support any "
>> + "bitrate-targetted rate control modes.\n");
>> return AVERROR(EINVAL);
>> }
>>
>> @@ -1320,27 +1323,90 @@ static av_cold int
>> vaapi_encode_init_rate_control(AVCodecContext *avctx)
>> hrd_buffer_size = avctx->rc_buffer_size;
>> else
>> hrd_buffer_size = avctx->bit_rate;
>> - if (avctx->rc_initial_buffer_occupancy)
>> + if (avctx->rc_initial_buffer_occupancy) {
>> + if (avctx->rc_initial_buffer_occupancy > hrd_buffer_size) {
>> + av_log(avctx, AV_LOG_ERROR, "Invalid RC buffer settings: "
>> + "must have initial buffer size (%d) < "
>> + "buffer size (%"PRId64").\n",
>> + avctx->rc_initial_buffer_occupancy, hrd_buffer_size);
>> + return AVERROR(EINVAL);
>> + }
>> hrd_initial_buffer_fullness = avctx->rc_initial_buffer_occupancy;
>> - else
>> + } else {
>> hrd_initial_buffer_fullness = hrd_buffer_size * 3 / 4;
>> + }
>> +
>> + if (avctx->rc_max_rate && avctx->rc_max_rate < avctx->bit_rate) {
>> + av_log(avctx, AV_LOG_ERROR, "Invalid bitrate settings: must have "
>> + "bitrate (%"PRId64") <= maxrate (%"PRId64").\n",
>> + avctx->bit_rate, avctx->rc_max_rate);
>> + return AVERROR(EINVAL);
>> + }
>> +
>> + if (avctx->rc_max_rate > avctx->bit_rate) {
>> + if (!(rc_attr.value & VA_RC_VBR)) {
>> + av_log(avctx, AV_LOG_WARNING, "Driver does not support "
>> + "VBR mode (%#x), using CBR mode instead.\n",
>> + rc_attr.value);
>> + ctx->va_rc_mode = VA_RC_CBR;
>> + } else {
>> + ctx->va_rc_mode = VA_RC_VBR;
>> + }
>> +
>> + rc_bits_per_second = avctx->rc_max_rate;
>> + rc_target_percentage = (avctx->bit_rate * 100) / avctx->rc_max_rate;
>> +
>> + } else if (avctx->rc_max_rate == avctx->bit_rate) {
>> + if (!(rc_attr.value & VA_RC_CBR)) {
>> + av_log(avctx, AV_LOG_WARNING, "Driver does not support "
>> + "CBR mode (%#x), using VBR mode instead.\n",
>> + rc_attr.value);
>> + ctx->va_rc_mode = VA_RC_VBR;
>> + } else {
>> + ctx->va_rc_mode = VA_RC_CBR;
>> + }
>>
>> - 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.
>> + if (rc_attr.value & VA_RC_VBR) {
>> + ctx->va_rc_mode = VA_RC_VBR;
>> +
>> + rc_bits_per_second = avctx->bit_rate + hrd_buffer_size;
>
> Why hrd_buffer_size is added? User may set a large hrd buffer size.
Given a buffer size and a target bitrate, the maximum bitrate in a second is
achieved by completely filling an empty buffer and also using all the bits
available from that second.
>> + rc_target_percentage = (avctx->bit_rate * 100) /
>> rc_bits_per_second;
>> + } else {
>> + ctx->va_rc_mode = VA_RC_CBR;
>> +
>> rc_bits_per_second = avctx->bit_rate;
>> rc_target_percentage = 100;
>> - } else {
>> - 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 = ((int64_t)hrd_buffer_size * 100 * 1000) /
>> + (rc_target_percentage * rc_bits_per_second);
>
> I think it should be (hrd_buffer_size * 1000) / rc_bits_per_second. Could you
> explain why is it multiplied by (100 / rc_target_percentage) here?
The target bitrate (avctx->bit_rate == rc_bits_per_second *
rc_target_percentage / 100) is the fill-rate of the buffer, so that's what we
need to divide the buffer size by to find how long it takes to fill and
therefore the effective window size.
>> +
>> + av_log(avctx, AV_LOG_VERBOSE, "RC mode: %s, %d%% of %"PRId64" bps "
>> + "over %d ms.\n", ctx->va_rc_mode == VA_RC_VBR ? "VBR" : "CBR",
>> + rc_target_percentage, rc_bits_per_second, rc_window_size);
>> + av_log(avctx, AV_LOG_VERBOSE, "RC buffer: %"PRId64" bits, "
>> + "initial fullness %"PRId64" bits.\n",
>> + hrd_buffer_size, hrd_initial_buffer_fullness);
>> +
>> + if (rc_bits_per_second > UINT32_MAX ||
>> + hrd_buffer_size > UINT32_MAX ||
>> + hrd_initial_buffer_fullness > UINT32_MAX) {
>> + av_log(avctx, AV_LOG_ERROR, "RC parameters of 2^32 or "
>> + "greater are not supported by VAAPI.\n");
>> + return AVERROR(EINVAL);
>> + }
>> +
>> + ctx->config_attributes[ctx->nb_config_attributes++] =
>> + (VAConfigAttrib) {
>> + .type = VAConfigAttribRateControl,
>> + .value = ctx->va_rc_mode,
>> + };
>> +
>> ctx->rc_params.misc.type = VAEncMiscParameterTypeRateControl;
>> ctx->rc_params.rc = (VAEncMiscParameterRateControl) {
>> .bits_per_second = rc_bits_per_second,
Thanks,
- Mark
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