On Tue, Feb 26, 2013 at 01:03:55PM -0500, Yonit Halperin wrote:
> The actual frames distribution does not necessarily fit the
> condition "at least one frame every (1000/rate_contorl->fps)
> milliseconds".
> For keeping the average frame rate close to the defined fps, we
> periodically measure the current average fps, and modify
> rate_control->adjusted_fps accordingly. Then, we use
> (1000/rate_control->adjusted_fps) as the interval between the
> frames.
ACK, some nitpicks (they are nitpicks, feel free to ignore).
> ---
> server/mjpeg_encoder.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 73 insertions(+), 2 deletions(-)
>
> diff --git a/server/mjpeg_encoder.c b/server/mjpeg_encoder.c
> index c124286..037a232 100644
> --- a/server/mjpeg_encoder.c
> +++ b/server/mjpeg_encoder.c
> @@ -51,6 +51,8 @@ static const int mjpeg_quality_samples[MJPEG_QUALITY_SAMPLE_NUM] = {20, 30, 40,
> #define MJPEG_CLIENT_POSITIVE_REPORT_TIMEOUT 2000
> #define MJPEG_CLIENT_POSITIVE_REPORT_STRICT_TIMEOUT 3000
>
> +#define MJPEG_ADJUST_FPS_TIMEOUT 500
> +
> /*
> * avoid interrupting the playback when there are temporary
> * incidents of instability (with respect to server and client drops)
> @@ -105,6 +107,7 @@ typedef struct MJpegEncoderBitRateInfo {
> uint32_t num_enc_frames;
> uint64_t sum_enc_size;
> } MJpegEncoderBitRateInfo;
> +
> /*
> * Adjusting the stream jpeg quality and frame rate (fps):
> * When during_quality_eval=TRUE, we compress different frames with different
> @@ -125,6 +128,10 @@ typedef struct MJpegEncoderRateControl {
> uint64_t byte_rate;
> int quality_id;
> uint32_t fps;
> + double adjusted_fps;
> + uint64_t adjusted_fps_start_time;
> + uint64_t adjusted_fps_num_frames;
Could be in an adjusted_fps struct.
> +
> /* the encoded frame size which the quality and the fps evaluation was based upon */
> uint64_t base_enc_size;
>
> @@ -132,6 +139,7 @@ typedef struct MJpegEncoderRateControl {
>
> uint64_t sum_recent_enc_size;
> uint32_t num_recent_enc_frames;
> +
> } MJpegEncoderRateControl;
>
> struct MJpegEncoder {
> @@ -355,6 +363,7 @@ static inline void mjpeg_encoder_reset_quality(MJpegEncoder *encoder,
> uint64_t frame_enc_size)
> {
> MJpegEncoderRateControl *rate_control = &encoder->rate_control;
> + double fps_ratio;
>
> rate_control->during_quality_eval = FALSE;
>
> @@ -362,7 +371,6 @@ static inline void mjpeg_encoder_reset_quality(MJpegEncoder *encoder,
> rate_control->last_enc_size = 0;
> }
>
> -
> if (rate_control->quality_eval_data.reason == MJPEG_QUALITY_EVAL_REASON_RATE_CHANGE) {
> memset(&rate_control->server_state, 0, sizeof(MJpegEncoderServerState));
> }
> @@ -371,8 +379,17 @@ static inline void mjpeg_encoder_reset_quality(MJpegEncoder *encoder,
> rate_control->quality_eval_data.max_quality_id = MJPEG_QUALITY_SAMPLE_NUM - 1;
> rate_control->quality_eval_data.max_quality_fps = MJPEG_MAX_FPS;
>
> + if (rate_control->adjusted_fps) {
> + fps_ratio = rate_control->adjusted_fps / rate_control->fps;
> + } else {
> + fps_ratio = 1.5;
Can you explain/document this number, how it was reached?
> + }
> rate_control->fps = MAX(MJPEG_MIN_FPS, fps);
> rate_control->fps = MIN(MJPEG_MAX_FPS, rate_control->fps);
> + rate_control->adjusted_fps = rate_control->fps*fps_ratio;
> + spice_debug("adjusted-fps-ratio=%.2f adjusted-fps=%.2f", fps_ratio, rate_control->adjusted_fps);
> + rate_control->adjusted_fps_start_time = 0;
> + rate_control->adjusted_fps_num_frames = 0;
> rate_control->base_enc_size = frame_enc_size;
>
> rate_control->sum_recent_enc_size = 0;
> @@ -630,6 +647,54 @@ end:
> }
> }
>
> +/*
> + * The actual frames distribution does not necessarily fit the condition "at least
> + * one frame every (1000/rate_contorl->fps) milliseconds".
> + * For keeping the average fps close to the defined fps, we periodically
> + * measure the current average fps, and modify rate_control->adjusted_fps accordingly.
> + * Then, we use (1000/rate_control->adjusted_fps) as the interval between frames.
> + */
> +static void mjpeg_encoder_adjust_fps(MJpegEncoder *encoder, uint64_t now)
> +{
> + MJpegEncoderRateControl *rate_control = &encoder->rate_control;
> + uint64_t adjusted_fps_time_passed;
> +
> + if (!encoder->rate_control_is_active) {
> + return;
> + }
> + adjusted_fps_time_passed = (now - rate_control->adjusted_fps_start_time) / 1000 / 1000;
> +
To avoid indentation and long lines you could negate the if and return
early.
> + if (!rate_control->during_quality_eval &&
> + adjusted_fps_time_passed > MJPEG_ADJUST_FPS_TIMEOUT &&
> + adjusted_fps_time_passed > 1000 / rate_control->adjusted_fps) {
> + double avg_fps;
> + double fps_ratio;
> +
> + avg_fps = ((double)rate_control->adjusted_fps_num_frames*1000) /
> + adjusted_fps_time_passed;
> + spice_debug("#frames-adjust=%lu #adjust-time=%lu avg-fps=%.2f",
> + rate_control->adjusted_fps_num_frames, adjusted_fps_time_passed, avg_fps);
> + spice_debug("defined=%u old-adjusted=%.2f", rate_control->fps, rate_control->adjusted_fps);
> + fps_ratio = avg_fps / rate_control->fps;
> + if (avg_fps + 0.5 < rate_control->fps &&
> + encoder->cbs.get_source_fps(encoder->cbs_opaque) > avg_fps) {
> + double new_adjusted_fps = avg_fps ?
> + (rate_control->adjusted_fps/fps_ratio) :
> + rate_control->adjusted_fps * 2;
> +
> + rate_control->adjusted_fps = MIN(rate_control->fps*2, new_adjusted_fps);
> + spice_debug("new-adjusted-fps=%.2f", rate_control->adjusted_fps);
> + } else if (rate_control->fps + 0.5 < avg_fps) {
> + double new_adjusted_fps = rate_control->adjusted_fps / fps_ratio;
> +
> + rate_control->adjusted_fps = MAX(rate_control->fps, new_adjusted_fps);
> + spice_debug("new-adjusted-fps=%.2f", rate_control->adjusted_fps);
> + }
> + rate_control->adjusted_fps_start_time = now;
> + rate_control->adjusted_fps_num_frames = 0;
> + }
> +}
> +
> int mjpeg_encoder_start_frame(MJpegEncoder *encoder, SpiceBitmapFmt format,
> int width, int height,
> uint8_t **dest, size_t *dest_len,
> @@ -645,9 +710,14 @@ int mjpeg_encoder_start_frame(MJpegEncoder *encoder, SpiceBitmapFmt format,
>
> clock_gettime(CLOCK_MONOTONIC, &time);
> now = ((uint64_t) time.tv_sec) * 1000000000 + time.tv_nsec;
> +
> + if (!rate_control->adjusted_fps_start_time) {
> + rate_control->adjusted_fps_start_time = now;
> + }
> + mjpeg_encoder_adjust_fps(encoder, now);
> interval = (now - rate_control->bit_rate_info.last_frame_time);
>
> - if (interval < (1000*1000*1000) / rate_control->fps) {
> + if (interval < (1000*1000*1000) / rate_control->adjusted_fps) {
> return MJPEG_ENCODER_FRAME_DROP;
> }
>
> @@ -772,6 +842,7 @@ size_t mjpeg_encoder_end_frame(MJpegEncoder *encoder)
> }
> rate_control->sum_recent_enc_size += rate_control->last_enc_size;
> rate_control->num_recent_enc_frames++;
> + rate_control->adjusted_fps_num_frames++;
> }
> rate_control->bit_rate_info.sum_enc_size += encoder->rate_control.last_enc_size;
> rate_control->bit_rate_info.num_enc_frames++;
> --
> 1.8.1
>
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