I have an application that transcodes a video frame by frame using FFMPEG and x264 encoder. I am looking to release this application but the licensing of x264 made me switch to using openh264 instead.
I managed to compile everything smoothly (openh264 then FFMPEG with enable-openh264). I am now trying to correct the encoder setup in my C code as what worked for libx264 doesn't work anymore. Unfortunately I found very limited C/C++ examples of FFMPEG/openh264, i would appreciate any link/hint.
I am using the following code (dec_ctx is the AVCodecContext of the video I am decoding)
enc_ctx->height = dec_ctx->height;
enc_ctx->width = dec_ctx->width;
enc_ctx->sample_aspect_ratio = dec_ctx->sample_aspect_ratio;
/* take first format from list of supported formats */
enc_ctx->pix_fmt = encoder->pix_fmts[0];
/* video time_base can be set to whatever is handy and supported by encoder */
enc_ctx->time_base = dec_ctx->time_base;
enc_ctx->gop_size = 120; /* emit one intra frame every twelve frames at most */
enc_ctx->max_b_frames = 16;
enc_ctx->scenechange_threshold = 0;
enc_ctx->rc_buffer_size = 0;
enc_ctx->me_method = ME_ZERO;
enc_ctx->ticks_per_frame = dec_ctx->ticks_per_frame * ifmt_ctx->streams[i]->time_base.den * ifmt_ctx->streams[i]->r_frame_rate.num/ifmt_ctx->streams[i]->r_frame_rate.den;
// Set Ultrafast profile. internal name for this preset is baseline
av_opt_set(enc_ctx->priv_data, "preset", "placebo", AV_OPT_SEARCH_CHILDREN);
I get the following errors in the output with the [OpenH264] tag:
[OpenH264] this = 0x0000000019C126C0, Warning:bEnableFrameSkip = 0,bitrate can't be controlled for RC_QUALITY_MODE,RC_BITRATE_MODE and RC_TIMESTAMP_MODE without enabling skip frame.
Output #0, mp4, to 'C:\Dev\temp\geoVid.mp4':
Stream #0:0: Video: h264 (libopenh264), yuv420p, 720x480, q=2-31, 200 kb/s, 90k tbn, 180k tbc
Stream #0:1: Audio: aac, 48000 Hz, stereo, fltp, 96 kb/s
[OpenH264] this = 0x0000000019C126C0, Warning:Actual input framerate fAverageFrameRate = 0.000000 is quite different from framerate in setting 60.000000, please check setting or timestamp unit (ms), start_Ts = 0
[OpenH264] this = 0x0000000019C126C0, Warning:Actual input framerate fAverageFrameRate = 0.000000 is quite different from framerate in setting 60.000000, please check setting or timestamp unit (ms), start_Ts = 0
The output video file just plays black frames. Any hint or link to some doc would be appreciated. I have been trying to understand these errors but not too sure how to enable "skip frame" or why it is complaining about my input framerate (this is the same input as when I encode successfully with libx264)
